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Journal of Strength and Conditioning Research, 2006, 20(1), 145–150
q 2006 National Strength & Conditioning Association
THE EFFECT OF THE DIRECTION OF GAZE ON THE
KINEMATICS OF THE SQUAT EXERCISE
DAVID V. DONNELLY,1 WILLIAM P. BERG,2 AND DARRYN M. FISKE3
1Department of Intercollegiate Athletics, Miami University, Oxford, Ohio 45056; 2Department of Physical
Education, Health and Sport Studies, Miami University, Oxford, Ohio 45056; 3Department of Athletics, St.
Bonaventure University, St. Bonaventure, New York 14778.
ABSTRACT. Donnelly, D., W.P. Berg, and D. Fiske. The effect of
the direction of gaze on the kinematics of the squat exercise. J.
Strength Cond. Res. 20(1):145–150. 2006.—The purpose of this
study was to determine whether the direction of gaze influences
the kinematics of the squat exercise. Ten men experienced in
the squat exercise performed a total of 30 repetitions of the
squat in the form of 2 sets of 5 repetitions under 3 different
conditions. Conditions varied with respect to the direction of the
subjects’ gaze as they performed the exercise. Condition D en-
tailed gazing downward at the intersection of the facing wall and
the floor throughout the exercise. Condition S required subjects
to gaze straight ahead at their own reflection (eyes) in the mirror
on the wall directly in front of them. Condition U involved gaz-
ing upward at the intersection of the facing wall and the ceiling
throughout the exercise. Dependent variables included the lin-
ear displacement of the bar and hip, linear velocity of the bar,
and the angular displacement/position and velocity of the head,
trunk, hip, and knee. The mean data were subjected to a re-
peated measures analysis of variance, and, where appropriate,
pairwise comparisons using Tukey’s Studentized Range Test.
The results revealed overall similarity in movement kinematics
when performing the squat exercise using the 3 different gaze
directions. In particular, the upward and straight gaze condi-
tions were not differentiated by the analysis. Conversely, the
downward gaze was shown to increase the extent of hip flexion
(F[2, 9] 5 4.82, p , .05), especially relative to the upward gaze,
and possibly trunk flexion as well (F[2, 9] 5 3.02, p 5 .07). In
terms of the practical application, because excessive hip and
trunk flexion in the squat are contraindicated, cautioning ath-
letes against allowing the head or direction of gaze to drop below
a neutral position appears to be warranted.
KEY WORDS. weight training, vision, stability
INTRODUCTION
T
he squat exercise involves most major muscle
groups of the trunk and legs, and is one of the
most beneficial muscle strengthening exercises.
The squat not only enhances performance in
many sports, but has become an important component of
general-purpose weight training programs as well. Be-
cause of the number of muscle groups involved, squats
also can positively stimulate the cardiovascular system
(8, 9, 10). Moreover, when performed correctly, the squat
can help prevent injuries (2, 6).
To obtain the desired training effects and to ensure
safety, proper technique should be used when performing
the squat. There is general agreement about what con-
stitutes appropriate squat technique, with at least 1 ex-
ception. There is some lack of clarity about how the head
should be positioned during the squat, or more precisely,
where a performer’s gaze should be directed—upward,
downward, or straight ahead? According to Fry, using an
incorrect head position can cause poor body alignment
and predispose an athlete to injury (5). What is the cor-
rect head position and/or direction of gaze in the squat?
According to Francoeur, lifters should focus on a spot
on the wall or ceiling, as this will help to keep the head
up throughout the entire motion (4). Global Health and
Fitness also recommends looking upward throughout the
exercise (7), whereas O’Shea simply recommends keeping
the head up (16). Westcott (17) and other professionals
instruct exercisers to keep the head neutral throughout
the exercise. Indeed, Kelso et al. advise that the head
should face straight forward throughout the exercise (12).
Some recommendations are more specific, such as that
the head and neck should be kept straight with the eyes
looking straight ahead (3, 5, 11,).
Some professionals warn against allowing the head
and eye focus to drop from a neutral position, arguing
that this could result in excessive forward lean as the
lifter descends (3). Forward lean is a nontechnical de-
scriptor of what we will refer to as trunk flexion. Trunk
flexion is the forward deviation of the trunk relative to
the vertical and can result from hip and knee flexion, as
well as ankle dorsiflexion. In short, a head-down position
during the squat exercise may increase the likelihood of
excessive trunk flexion. Several authors have suggested
that excessive trunk flexion during the squat can cause
undue stress to be applied to the lumbar spine, and thus
increase the chance of injury (3, 5, 14, 15).
On the contrary, Hill warns against using a head-up,
eyes-up technique, arguing that balance is compromised,
increasingly so during descent, making lower back strain
more likely (3). Instead, Hill argues that the head and
eyes should be straight or slightly down throughout the
exercise. The latter recommendation is the only one, to
our knowledge, suggesting that a downwardly directed
gaze or head position is acceptable. Nonetheless, in spite
of the general bias among experts against looking down-
ward during the squat, athletes and weight trainers
sometimes can be observed doing so.
Adding to the uncertainty about appropriate head po-
sition and direction of gaze during the squat exercise is
the fact that head position and direction of gaze are not
synonymous. Ignoring the movement of the body as a
whole, humans can redirect gaze by (a) moving the head
with the eyes fixed in the head, (b) moving the eyes with
the head fixed, or (c) moving the eyes and the head si-
multaneously. A recommendation such as O’Shea’s to
keep the head up during the squat (16) does not ensure
that gaze will be directed upward as well. Of course, head
position and direction of gaze likely are related; concern-
146 DONNELLY, BERG, AND FISKE
ing recommendations for squat technique, however, it is
a mistake to assume they are equivalent. What is it that
matters: head position, direction of gaze, both, or neither?
Theoretically, the direction of gaze during the squat
exercise is potentially important, because it could affect
posture and stability. Vision can be critical for movement
control during the squat, particularly regarding balance/
stability (1). Accurate perception of self-motion is funda-
mental to maintaining stability, and the direction of gaze
could influence a lifter’s perception of self-motion. For ex-
ample, looking upward toward the ceiling during the
squat exercise could decrease sensitivity to information
about the position of one’s body relative to the proximal
support surface (floor). Information about one’s position
relative to the floor is salient because it is useful for de-
termining when to terminate the descent portion of the
exercise and to begin the ascent. Selecting the correct
point to change direction is critical, because a failure to
do so could result in a loss of balance, leading to injury
of the knee or back, or even causing the athlete to fall.
In contrast, directing one’s gaze downward toward the
floor during the squat could decrease sensitivity to infor-
mation about the position of one’s body relative to a wall
or objects directly in front of the lifter. Perceiving ap-
proach to or withdrawal from objects and surfaces direct-
ly in front of us allows us to perceive forward and back-
ward sway, respectively, and is critical for maintaining
an upright posture (13). By looking at the floor, a per-
former might fail to perceive postural sway in time to
retard the forward or backward rotation of the body,
which could result in a fall.
What about head position during the squat exercise?
Theoretically, head position is important because it could
possibly affect posture and stability, though more
straightforwardly so than direction of gaze influences sta-
bility. For example, Fry contends that the head and neck
can be considered continuations of the vertebral column
(5), implying that head position has a direct effect on body
alignment, irrespective of the direction of gaze. It is ob-
vious that improper body alignment, such as allowing
one’s center of gravity to escape the confines of the base
of support, could be detrimental to performance or even
dangerous.
Because of the lack of agreement concerning head po-
sition and direction of gaze in the squat exercise, and giv-
en its probable importance to stability and safety during
the performance of that exercise, the purpose of this
study was to determine whether direction of gaze influ-
ences the kinematics of the squat. As previously ex-
plained, when referring to the squat exercise, strength
and conditioning professionals appear to consider head
position and direction of gaze to be synonymous or nearly
so, but they are not. We chose to manipulate the direction
of gaze rather than head position, because the former is
far more easily and precisely controlled. Naturally, anal-
yses of the results included the extent to which direction
of gaze and head position were associated.
We also chose to evaluate anterior/posterior displace-
ment of the bar, as well as hip and linear velocity of the
bar, as measures of postural sway, and thus, indicators
of stability. We also chose to characterize the angular ki-
nematics of the trunk, hip, and knee to determine if the
direction of gaze affects the overall coordination dynamics
of the squat. Because of the potential link between exces-
sive trunk flexion, undue stress to the lumbar spine, and
injury risk (3, 6, 14, 15), we were particularly interested
in evaluating trunk flexion across different gaze direc-
tions. Our hypotheses were that a downward gaze would
result in a greater trunk flexion, as well as greater pos-
tural sway (instability), than either the straight or up-
ward gaze conditions. We also anticipated that the up-
ward and straight gaze directions would yield similar lin-
ear and angular squat kinematics.
METHODS
Experimental Approach to the Problem
A repeated-measures design was used to determine the
effect of the direction of gaze (downward, straight ahead,
or upward) on the kinematics of the squat exercise. De-
pendent variables included the linear displacement of the
bar and hip, linear velocity of the bar, and the angular
displacement/position and velocity of the head, trunk, hip,
and knee.
Subjects
The subjects for this study consisted of 10 young men
(mean age 5 20; SD 5 1.3; range, 18–22 years) who were
members of the Miami University football team. Each
subject had at least 1 year of experience performing the
squat exercise. The subjects ranged in height from 1.78–
1.96 m and ranged in weight from 84–136.2 kg. The in-
vestigation was approved by the Miami University Insti-
tutional Review Board for Human Subjects.
Procedures
The apparatus used to perform the squat exercise con-
sisted of a power rack, a York Olympic 20.43-kg bar (York
Barbell Co., York, PA), and Olympic-sized weight plates.
The rack was positioned such that subjects faced a mir-
rored wall (at a distance of 1.5 m.) while performing the
exercise. Subjects performed a total of 30 repetitions of
the squat exercise in the form of 2 sets of 5 repetitions
under 3 different conditions. The conditions varied with
respect to the direction of the subjects’ gaze as they per-
formed the squat. Condition D entailed gazing downward
at the intersection of the facing wall and the floor
throughout the exercise. Condition S required subjects to
gaze straight ahead at their own reflection (eyes) in the
mirror on the wall directly in front of them. Condition U
involved gazing upward at the intersection of the facing
wall and the ceiling (height 5 2.79 m) throughout the
exercise. The order in which the conditions were per-
formed was counterbalanced across subjects. The inten-
sity for each subject was set at 25% of his 1 repetition
maximum (1RM) in the squat exercise. The purpose of
choosing a relatively light load was to minimize the ex-
tent to which fatigue would influence squat kinematics.
Normally, one could expect counterbalancing the order in
which conditions are presented to completely control for
any order effect resulting from fatigue. However, given
that the differences in kinematics we could foresee as a
result of manipulating the direction gaze were not dra-
matic, we choose to try to minimize the effect of fatigue.
Three minutes of recovery was afforded between each set
of 5 repetitions.
A Panasonic WV-D5100HS SVHS video camera (Pan-
asonic, Secaucus, NJ) operating at 60 Hz and with a shut-
ter speed of 1/250 second was positioned 5.5 m to the right
of the subject and was used to record each trial. The cam-
DIRECTION OF GAZE IN THE SQUAT 147
FIGURE 1. Reflective marker locations and angle
designations.
TABLE 1. Mean total linear displacement of the bar and hip.*
Condition
Downward gaze Straight gaze Upward gaze
Mean total horizontal displacement of the bar (m) 0.12 0.11 0.10
SD 0.04 0.05 0.04
Mean total vertical displacement of the bar (m) 0.75 0.74 0.73
SD 0.08 0.09 0.08
Mean total horizontal displacement of the hip (m) 0.14 0.14 0.13
SD 0.02 0.02 0.03
Mean total vertical displacement of the hip (m) 0.39 0.38 0.38
SD 0.08 0.08 0.08
* Results were not statistically significant.
era was level, 90 cm from the floor, and was oriented with
its optical axis perpendicular to a subject’s sagittal plane
of motion. The camera was equipped with a halogen flood
lamp that illuminated reflective markers on the subject.
As illustrated in Figure 1, the reflective markers were
located (a) just below the superciliary arch near the right
eye, (b) at the greater trochanter of the right hip, (c) at
the lateral articulation of the right knee, (d) at the lateral
malleolous of the right ankle, and (e) at the end of the
squatting bar.
The third trial from each set of 5 repetitions was dig-
itized using a motion measurement system from Peak
Performance Inc (Vicon-Peak, Centennial, CO). Thus, 6
trials were digitized for each subject (2 for each condi-
tion), for a total of 60 trials. The landmarks denoted by
the reflective markers were automatically digitized begin-
ning with the video frame displaying the first downward
movement of the bar, and continued for each of 176 con-
secutive frames (2.93 seconds). Once digitizing was com-
pleted, the data was smoothed using a Butterworth dig-
ital filter, and the dependent variables were computed.
Statistical Analyses
Variables included the linear displacement of the bar and
hip, linear velocity of the bar, and the angular displace-
ment/position and velocity of the head, trunk, hip, and
knee (refer to Figure 1 for angle designations). To ascer-
tain whether there were differences among the 3 condi-
tions, the mean data were subjected to a repeated mea-
sures analysis of variance (ANOVA), and where appro-
priate, pairwise comparisons using Tukey’s Studentized
Range Test. The correlation between the direction of gaze
and mean head position was computed using a Spear-
man’s rho (rank) correlation. An alpha level of 0.05 was
used for the statistical tests.
RESULTS
Linear Kinematics of the Bar and Hip
As shown in Table 1, a repeated measures ANOVA failed
to reveal differences in the mean total horizontal and ver-
tical bar displacements or the mean total horizontal and
vertical hip displacements: F(2, 9) 5 0.81, p . 0.05; F(2,
9) 5 1.18, p . 0.05; F(2, 9) 5 0.77, p . 0.05; and F(2, 9)
5 0.87, p . 0.05, respectively. As is evident from the data
presented in Table 2, there were likewise no significant
differences in peak linear velocity of the bar in the down-
ward, upward, forward, or backward directions: F(2, 9) 5
0.74, p . 0.05; F(2, 9) 5 0.53, p . 0.05; F(2, 9) 5 1.04, p
. 0.05; and F(2, 9) 5 0.41, p . 0.05, respectively. The
lack of differences in the data characterizing horizontal
(i.e., anterior-posterior) motion indicates that postural
sway, and thus stability, was not affected by the direction
of gaze.
Angular Kinematics
The mean angular head position was computed to deter-
mine the extent to which the different gaze conditions
influenced head position. The mean head angles are
shown in Table 3. The repeated measures ANOVA for
head angle was significant (F[2, 9] 5 35.77, p , 0.0001).
Pairwise comparisons using Tukey’s Studentized Range
Test revealed significant differences between condition D
and each of the other conditions (S: difference 5 22.72,
95% confidence limits [CL] 5 13.02, 32.42; U: difference
5 31.05, 95% CL 5 21.35, 40.75). However, the difference
148 DONNELLY, BERG, AND FISKE
TABLE 2. Mean peak linear velocity of the bar for 3 gaze directions.*
Condition
Downward gaze Straight gaze Upward gaze
Mean peak velocity of the bar in downward direction (m·s21) 0.92 0.94 0.91
SD 0.15 0.13 0.14
Mean peak velocity of the bar in upward direction (m·s21) 1.06 1.09 1.08
SD 0.09 0.08 0.10
Mean peak velocity of the bar in forward direction (m·s21) 0.15 0.15 0.13
SD 0.04 0.06 0.04
Mean peak velocity of the bar in backward direction (m·s21) 0.16 0.15 0.16
SD 0.05 0.06 0.07
* Results were not statistically significant.
TABLE 3. Mean maximum angular displacement of the trunk, hip, knee, and mean angular position of the head for 3 gaze
directions.*
Condition
Downward gaze Straight gaze Upward gaze
Mean maximum trunk flexion† (8) 217 213 212
SD 7 12 12
Mean maximum hip flexion‡ (8) 77 84 86
SD 7 15 14
Mean maximum knee flexion (8) 82 83 85
SD 11 12 12
Mean head angle§ (8) 97 75 66
SD 12 5 10
* For the trunk and head, larger values represent greater flexion. For the hip and knee, smaller values represent greater flexion.
See Figure 1 for angle designations.
† P 5 0.07.
‡ p , 0.05 (pairwise comparisons revealed a single significant difference between conditions D and U).
§ p , 0.0001 (pairwise comparisons revealed significant differences between conditions D and S, and D and U).
between conditions S and U did not achieve significance
(difference 5 8.33, 95% CL 5 21.37, 18.03). The corre-
lation coefficient between direction of gaze and mean
head position was 0.79 (p , 0.0001). The results indicate
that although direction of gaze and head position were
strongly related, they should not be considered equiva-
lent.
Also apparent in Table 3 is the fact that mean maxi-
mum trunk, hip, and knee flexion were each greatest
when the direction of gaze was directed downward (con-
dition D). (Note that for the trunk, larger values repre-
sent greater flexion, whereas for the hip and knee, small-
er values represent greater flexion.) The repeated mea-
sures ANOVA for mean maximum hip flexion was signif-
icant (F[2, 9] 5 4.82, p , 0.05), with the lone significant
difference found between conditions D and U. In other
words, hip flexion was more severe when using the down-
ward gaze than the upward gaze (difference 5 8.32, 95%
CL 5 1.05, 15.58). The repeated measures ANOVA for
mean maximum trunk flexion approached significance
(F[2, 9] 5 3.02, p 5 0.07), with condition D exceeding both
conditions S and U by 4 and 58, respectively. In other
words, trunk flexion demonstrated a tendency to be more
severe when using the downward gaze than when using
the straight or upward conditions, but the difference was
not statistically significant. The repeated measures AN-
OVA for mean maximum knee flexion was not significant
(F[2, 9] 5 0.48, p . 0.05), indicating that knee flexion
was unaffected by gaze direction.
As shown in Table 4, the repeated measures ANOVAs
failed to reveal statistically significant differences among
conditions for peak trunk, hip, and knee flexion velocity:
F(2, 9) 5 1.81, p . 0.05; F(2, 9) 5 0.15, p . 0.05; and
F(2, 9) 5 0.28, p . 0.05, respectively. There were likewise
no significant differences among conditions for peak
trunk, hip, and knee extension velocity: F(2, 9) 5 0.58, p
. 0.05; F(2, 9) 5 0.36, p . 0.05; and F(2, 9) 5 2.02, p .
0.05, respectively.
DISCUSSION
The purpose of this study was to begin to address the lack
of clarity about head position or gaze direction during the
squat exercise. Based on current technical standards for
performing the squat exercise, as well as theoretical im-
plications of head position and direction of gaze on pos-
tural stability, we hypothesized that a downward gaze
(condition D) would result in a greater maximum trunk
flexion, as well as greater instability as determined by the
total anterior-posterior displacement of the bar and hip.
Conversely, we anticipated that an upward and straight-
ahead gaze (conditions U and S, respectively) would re-
sult in similar linear and angular kinematics.
First, however, we evaluated the extent to which the
direction of gaze and head position were equivalent. As
expected, there was a strong relationship between direc-
tion of gaze and mean head position, yet it was not perfect
(r 5 0.79, R2 5 62.4%). Strength and conditioning profes-
sionals should be aware of the lack of a one-to-one map-
ping between direction of gaze and head position, and
DIRECTION OF GAZE IN THE SQUAT 149
TABLE 4. Mean peak angular velocity of the trunk, hip, and knee for three gaze directions.
Condition
Downward gaze Straight gaze Upward gaze
Mean peak trunk flexion velocity (8·s21) 45 42 40
SD 8 10 6
Mean peak hip flexion velocity (8·s21) 102 101 100
SD 15 15 13
Mean peak knee flexion velocity (8·s21) 111 108 107
SD 22 21 19
Mean peak trunk extension velocity (8·s21 46 46 44
SD 5 9 7
Mean peak hip extension velocity (8·s21) 114 116 117
SD 14 10 18
Mean peak knee extension velocity (8·s21) 113 116 122
SD 24 23 29
* Results were not statistically significant.
should develop instructional cues for the squat exercise
accordingly. Because we directly manipulated only the
gaze direction in this study, we will refer only to it in the
discussion.
Our hypotheses that condition D would result in
greater total anterior-posterior motion of the bar and hip
(postural sway) were not supported. Likewise, mean peak
linear velocity of the bar in the downward, upward, for-
ward, or backward direction did not differ across condi-
tions. In sum, based on measures of total bar and hip
displacement, as well as peak bar velocity, we must con-
clude that direction of gaze did not influence postural
sway, and thus stability, in the squat exercise.
Mean maximum trunk flexion was an average of 4.58
greater in condition D than in condition S or U. The sta-
tistical analysis on this variable approached significance
(p 5 0.07) and thus there is reason to believe that the
downward gaze did result in greater trunk flexion than
did conditions U and S. Moreover, under condition D,
mean maximum hip flexion was 9 and 78 greater than
conditions U and S, respectively, with the difference be-
tween D and U achieving statistical significance. It is
noteworthy that squat depth did not differ among condi-
tions (as shown in Table 1—vertical displacement of the
hip), nor did maximum knee flexion differ, indicating that
the increase in hip flexion observed in condition D was
not offset by greater knee flexion (i.e., a deeper squat).
Our findings appear to confirm the efficacy of the rec-
ommendation made by some strength and conditioning
professionals against allowing the head and eye focus to
drop below a neutral position as a means of preventing
excessive trunk flexion (3). What are the implications of
greater trunk flexion in the squat? Of course, some trunk
flexion is necessary, but excessive flexion could put an
increased torque on the lower back musculature, possibly
putting the athlete at greater risk of injuries such as mus-
cle strains, disc herniations, and spondylolysis (stress
fracture of the vertebral column) (3, 5, 14, 15). The injury
risk that is speculated to accompany excessive trunk flex-
ion resulting from a downward gaze might be exacerbated
if accompanied by a concomitant increase in flexion ve-
locity. However, analyses failed to reveal statistically sig-
nificant differences among conditions for peak trunk flex-
ion velocity.
Our study had 2 noteworthy limitations. First, sub-
jects in the study were all college football players with a
minimum of 1 year of experience performing the squat
exercise. Therefore, the results should not necessarily be
generalized to younger athletes or those with less expe-
rience performing the squat. Second, subjects performed
the squat using 25% of their 1RM. It is possible that the
effect of gaze direction on movement kinematics could dif-
fer from that observed in this study when using a higher
intensity exercise. This question will need to be addressed
in future research, but for now we must emphasize that
the results of this study apply only to low-intensity squat-
ting. It is also important to emphasize that the significant
and nearly significant differences in mean maximum hip
and trunk flexion, respectively, were found between con-
ditions D and U only. Thus, it is important to be precise
in our conclusion that the downward gaze resulted in
greater hip and trunk flexion than the upward gaze, but
not greater than the straight gaze.
PRACTICAL APPLICATIONS
This study of male collegiate football players revealed
overall similarity in movement kinematics when perform-
ing the squat exercise using 3 different gaze directions:
upward, straight, and downward. Our study was unable
to differentiate between the straight and upward gaze di-
rections. Conversely, the downward gaze was shown to
increase the extent of hip flexion and possibly trunk flex-
ion as well, especially relative to the upward gaze. Be-
cause excessive hip and trunk flexion in the squat are
contraindicated, cautioning athletes against allowing the
head or direction of gaze to drop below a neutral position
appears to be warranted.
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Training Techniques (4th ed.). Quincy, MA: McGraw-Hill. 1994.
Acknowledgments
We would like to thank Michael Hughes for his contribution to
this study.
Address correspondence to William P. Berg, [email protected]
muohio.edu.
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Original Research
Kinematic Differences Between the Front and Back
Squat and Conventional and Sumo Deadlift
Jovana Kasovic,1 Benjamin Martin,1 and Christopher A. Fahs2
1
Department of Exercise Science, Lindenwood University Belleville, Belleville, Illinois; and
2
College of Health Sciences, Logan
University, Chesterfield, Missouri
Abstract
fferences between the front and back squat and conventional and sumo deadlift. J Strength Cond Res 33(12): 3213–3219,
2019—The average concentric velocity (ACV) of a resistance exercise movement is inversely related to the load lifted. Previous work
suggests that different resistance exercises differ in ACV at the same relative load. Currently, there is limited evidence to determine
whether the style of exercise (e.g., front or back squat [BS]; sumo-style or conventional-style deadlift) also affects the load-velocity
profile or other kinematic variables such as the peak concentric velocity (PCV) and linear displacement (LD). The purpose of this
study was to compare the kinematics (ACV, PCV, and LD) between the front squat (FS) and BS as well as between the conventional
deadlift (CD) and sumo deadlift (SD). In a randomized order, 24 men and women (22 6 3 years) performed a 1 repetition maximum
(1RM) protocol for the FS, BS, CD, and SD over 4 visits to the laboratory. Barbell kinematics were recorded during all submaximal
and maximal repetitions performed during the 1RM protocol using the Open Barbell System. Kinematic data were pooled into
categories based on the percentage of the 1RM lifted in 10% increments (e.g., 30–39% 1RM, 40–49% 1RM, etc.) and compared
between exercises. Correlations between kinematic data for the FS and BS and for the CD and SD were examined at each relative
load. No differences in kinematics were observed between the FS and BS at any load (p . 0.05). However, FS and BS ACV was
weakly correlated (r , 0.4) at high (.80% 1RM) loads. Differences in LD were apparent between the SD and CD at all loads
(30–100% 1RM) with the SD having a smaller LD compared with the CD (p , 0.05). Average concentric velocity was not different
between the SD and CD at the 1RM (0.25 6 0.09 vs. 0.25 6 0.06 m·s21; p 5 0.962) but was different at 80–89% 1RM (0.35 6 0.08
vs. 0.40 6 0.07; p 5 0.017), 70–79% 1RM (0.41 6 0.08 vs. 0.46 6 0.06; p 5 0.026), and 40–49% 1RM (0.66 6 0.09 vs. 0.77 6
0.08; p , 0.001). In addition, SD and CD ACV values showed no relationships (p . 0.05) at any loads except at the 1RM (r 5 0.433;
p , 0.05). These results suggest individual load-velocity profiles for the FS and BS as well as for the CD and SD should be used for
training purposes.
Key Words: average concentric velocity, velocity-based training, barbell, resistance exercise
Introduction
The inverse relationship between the load lifted during a re-
sistance training exercise and the velocity of movement, average
concentric velocity (ACV), is well established and has been used
to predict the 1 repetition maximum (1RM) (13,15). The ACV
during resistance exercise has also been used for prescribing
training, known as velocity-based training (VBT) (16). Typically
a range of ACV values may be used for prescribing training loads
because there is variability between individuals in ACV at a given
load (2). The load-ACV profile may also differ based on the ex-
ercise because differences in ACV have been shown at various
loads between barbell exercises including the squat, bench press,
deadlift, and overhead press (7). Variations in the style of exercise
performed may also affect the load-velocity profile.
Several studies have examined the load-velocity relationship in the
back squat (BS) performed using a smith machine and shown it to be
strong and linear (3,8,15,18) although a similar relationship has been
shown for the free weight BS (1,7). However, the load-velocity re-
lationship in the free weight BS may be weaker than the relationship
observed with the smith machine BS due to variation in the technique
in the free weight BS at high loads (2). For trainees performing other
variations of the squat, such as the front squat (FS), the load-velocity
profile may be different due to different joint angles and muscle re-
cruitment (22). Studies have documented differences in kinematics
between the FS and BS lifts primarily showing the BS elicits more acute
hip angle at the bottom of the motion compared with the FS (4,22).
Greater quadriceps muscle activity has also been shown in the FS
compared with the BS (22), although this has not been found in all
studies (10). A comparison between the FS and BS load-velocity profile
showed no differences between the FS and BS in a sample of male
Division I college baseball players (20). However, the load-velocity
profile has been shown to differ between men and women (1), which
may be due to differences in strength. Thus, it would be beneficial to
coaches and trainees if similar evidence existed comparing the load-
velocity profiles of the FS and BS from both male and female trainees.
Previous work has also investigated biomechanical differences
between the sumo deadlift (SD) and the conventional-style
deadlift (CD). With a greater stance width and slightly more
narrow grip width for the SD compared with the CD, there are
differences in the amount of mechanical work and stress placed
on various joints between the SD and CD (5). Electromyography
recorded during the 2 deadlift styles suggests greater knee ex-
tensor muscle activity during the SD compared with the CD (6).
McGuigan and Wilson (17) provided a thorough description of
the kinematic differences between the 2 styles of deadlift in
competitive powerlifters during competition; the authors
Address correspondence to Dr. Christopher A. Fahs, [email protected]
Journal of Strength and Conditioning Research 33(12)/3213–3219
ª 2019 National Strength and Conditioning Association
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Copyright © 2019 National Strength and Conditioning Association. Unauthorized reproduction of this article is prohibited.
mailto:[email protected]
observed that the SD has a shorter range of motion than the CD
while both lifts take the same time to complete. These results
would suggest that the ACV of the SD would be lower than for the
CD at a given load, but this has not been demonstrated at sub-
maximal loads or in trainees other than competitive powerlifters.
It is possible that the kinematics of the deadlift may differ between
competitive lifters and recreational lifters as the ACV at maximal
loads has been shown to be inversely related to relative strength
(7) and also lower in experienced lifters compared with novice
lifters (23). If differences in ACV exist between the 2 deadlift styles
at submaximal loads, this would be important to know for those
using VBT for different types of deadlift training. Therefore, the
purpose of this study was to compare kinematic differences
(ACV, peak concentric velocity [PCV], and linear displacement
[LD]) at submaximal and maximal loads between the CD and SD
as well as the FS and BS in a sample of men and women. We
hypothesized that the BS would elicit greater ACV and PCV
values compared with the FS at the same relative load and that the
CD would elicit greater ACV, PCV, and LD values compared with
the SD at the same relative load. We also hypothesized that men
would exhibiter greater ACV and PCV values compared with
women for all exercises.
Methods
Experimental Approach to the Problem
Subjects visited the laboratory on 4 occasions. For each visit,
subjects were instructed to avoid strenuous exercise with the
lower body for 24 hours before testing. During the first visit, the
subject’s anthropometrics were measured, and the training his-
tory was recorded. During this visit and each of the subsequent 3
visits, subjects completed a 1RM protocol for the FS, BS, SD, or
conventional deadlift (CD). Each visit was separated by at least 48
hours, and the exercise order was randomized.
Subjects
Twenty-sevensubjects gave written informed consent to participate
in this study. Owing to circumstances unrelated to the study, 3
subjects only completed only 1 testing session, whereas 1 subject
only completed the SD and CD trials leaving a final sample of 24
subjects (15 men and 9 women) for the SD vs. CD comparison and
23 subjects (14 men and 9 women) for the FS vs. BS comparison.
Subjects (N 5 24) were 22 6 3 years old [age range: 18–35 years]
with a body mass of 77.2 6 13.9 kg and height of 1.73 6 0.10 m.
All subjects were currently training with at least 1 form of the squat
(FS or BS) and 1 form of the deadlift (SD or CD), familiar with both
styles of each lift, and most subjects had at least 1 year of training
experience with both types of squat (18 of 23 subjects) and both
types of deadlift (18 of 24 subjects). The Lindenwood University’s
institutional review board approved this study (approval #00065),
and all subjects were informed of the risks and benefits of the study
before providing written informed consent (Table 1).
Procedures
Anthropometrics. Standing height was recorded to the nearest
0.01 m with a standard stadiometer (Tanita HR-200; Tanita
Corporation, Arlington Heights, IL), and body mass was recor-
ded with a digital scale (Tanita BWB-800S Doctors Scale; Tanita
Corporation) to the nearest 0.1 kg. Humerus length was mea-
sured with a tape measure as the straight line distance between the
acromion process and olecranon process on the right arm and
recorded to the nearest 0.01 m. Femur length was measured with
a tape measure with the subject seated as the straight line distance
between the greater trochanter and lateral epicondyle of the femur
and recorded to the nearest 0.01 m.
Training History. Subjectswereaskedhowmanyyearsofexperience
they hadperforming eachof the lifts (training age) andhowfrequently
(training sessions per week) they perform each of the lifts (frequency).
One-Repetition Maximum Protocol. Subjects performed a stan-
dardized warm-up on a Monark cycle ergometer (Monark
Ergomedic 828 E; Monark, Vargerb, Sweeden) at a self-selected
light-intensity (i.e., rating of perceived exertion 9–11 on the Borg
6–20 scale) for 5 minutes. Using the subject’s estimated 1RM
(e1RM), the loads for the warm-up sets were determined. The
subject’s e1RM was based on their recent training performance
using the %1RM-repetition relationship as a guide (19). If the
subject did not have experience with 1 style of deadlift, it was
estimated that their 1RM for that style of deadlift would be
5–10% than that of the style of deadlift with which they had
experience; if the subject did not have experience with 1 style of
squat, it was estimated that their FS 1RM was ;75–80% of their
BS 1RM based previous research (22). Following the protocol
recommended by Jovanovic and Flanagan (14), warm-up sets
consisted of 2–3 repetitions with 30–40% of the e1RM, 2 repe-
titions with 40–50% of the e1RM, 1–2 repetitions with 60–70%
of the e1RM, 1 repetition with 70–80% of the e1RM, and 1
repetition with 80–85% of the e1RM. A minimum of 3 minutes
was allotted between warm-up sets. Subjects were instructed to
lift with maximal effort and to move the weight as fast as possible
on every repetition regardless of the load being lifted, and they
were encouraged to maintain consistent technique for each at-
tempt. After the last warm-up attempt, the 1RM was determined
as the heaviest load (kg) lifted through a full range of motion. Up
to 5 attempts were used to determine the 1RM, and a minimum of
3 minutes rest was allotted between each attempt.
Barbell Lifts. For the FS and BS, the subject began with the hips
and knees fully extended and descended until the crease of the hip
was level or below the top of the patella when viewed from the
side. Completion of a successful repetition required the subject to
then return to the standing position with the knees and hips fully
extended. Verbal feedback was provided to the subjects during
warm-up sets to ensure proper depth; any repetitions that did not
reach proper depth were not used in the analysis. For the BS,
subjects positioned the bar either over the rear deltoids (low bar)
or upper trapezius (high bar) based on personal preference. For
the FS, subjects positioned the bar over the anterior deltoids with
the arms in either the front rack or crossed-arm position based on
Table 1
Subject characteristics.*
Men (n 5 15) Women (n 5 9) p
Age (y) 21 6 2 22 6 5 0.335
Body mass (kg) 82.9 6 13.8 67.7 6 7.7 0.006
Height (m) 1.78 6 0.06 1.63 6 0.06 ,0.001
BMI (kg·m22) 25.9 6 3.7 25.7 6 4.3 0.924
Humerus length (m) 0.42 6 0.04 0.37 6 0.03 0.005
Femur length (m) 0.44 6 0.04 0.42 6 0.04 0.427
*BMI 5 body mass index. Subject characteristics were measured mean 6 SD.
Squat and Deadlift Kinematics (2019) 33:12
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personal preference. For the CD and SD, the barbell began mo-
tionless on the ground. For the CD, grip width was greater than
the stance width, and for SD, the grip width was less than the
stance width; specific stance and grip width was left to personal
preference. Subjects were encouraged to use either the alternate
grip (1 palm pronated and the other supinated) or the hook grip
for the deadlift; the grip used was same for both deadlift styles
within each subject. A full range of motion for the CD and SD was
achieved with the subject holding the barbell at arm’s length with
the hips and knees fully extended. No hitching or supporting the
barbell on the thighs during the lift was permitted for either the SD
or CD.
Barbell Kinematics. The Open Barbell System (OBS; Squats &
Science Labs LLC, Seattle, WA) was attached to the barbell
during the 1RM protocol, which recorded the ACV, PCV, and the
LD of each repetition. This system uses a cable connected to the
barbell similar to the TENDO power and speed analyzer and
GymAware systems. Similar to the TENDO power and speed
analyzer, this device provides 1-dimensional measurements of
velocity and displacement. According the manufacturer, the OBS
device calculates kinematic variables every 2.8 mm of displace-
ment during a repetition (21). Although no longer currently
available to the public, this device provides a valid measurement
of ACV and PCV compared with a 3D motion capture system (9).
For the FS and BS, the cable was attached to the sleeve of the
barbell, and the unit was placed in a position so that the cable was
vertical in the frontal and sagittal plane during the concentric
portion of each repetition. For the CD and SD, the unit was placed
under the center of the barbell between the subject’s feet with the
cable attached to the center of the barbell with vertical alignment
in the frontal and sagittal plane during each repetition. For the
warm-up sets in which more than 1 repetition was performed, the
repetition with the greatest ACV was used for analysis.
Load-Velocity Comparison. From the 1RM testing protocol, we
obtained kinematic data during the 1RM data on each subject.
The load of each warm-up set and each successful 1RM attempt
less than the actual 1RM was calculated as a percentage of the
actual 1RM and categorized as follows: 30–39%, 40–49%,
Table 2
Comparison between the front and back squat.*
Front squat Back squat
N Lift comparison pMen Women Men Women
Training age (y) 3.3 6 3.1 4.7 6 2.8 4.9 6 3.1 6.3 6 1.7 23 ,0.001
Frequency (d·wk21) 0.6 6 0.7 0.6 6 0.7 1.3 6 0.9 1.4 6 0.8 23 0.001
One year of experience with exercise (n) 11 8 14 9 23
1RM (kg) 108.6 6 33.2 61.7 6 9.7† 131.8 6 40.7 75.0 6 12.7† 23 ,0.001
Relative 1RM 1.31 6 0.28 0.91 6 0.12† 1.59 6 0.38 1.11 6 0.18† 23 ,0.001
1RM
ACV (m·s21) 0.32 6 0.08 0.29 6 0.08 0.31 6 0.08 0.25 6 0.08 23 0.259
PCV (m·s21) 0.68 6 0.10 0.74 6 0.21 0.79 6 0.21 0.73 6 0.23 23 0.152
LD (m) 0.499 6 0.078 0.505 6 0.044 0.527 6 0.062 0.481 6 0.093 23 0.732
90–99% 1RM
ACV (m·s21) 0.36 6 0.05 0.43 6 0.16 0.42 6 0.07 0.26 6 0.04† 7 0.268
PCV (m·s21) 0.71 6 0.12 0.81 6 0.34 0.95 6 0.18 0.75 6 0.33 7 ,0.001
LD (m) 0.500 6 0.056 0.494 6 0.007 0.550 6 0.065 0.499 6 0.086 7 0.117
80–89% 1RM
ACV (m·s21) 0.48 6 0.09 0.45 6 0.04 0.50 6 0.10 0.40 6 0.03† 16 0.930
PCV (m·s21) 0.86 6 0.16 0.99 6 0.16 1.00 6 0.28 0.99 6 0.14 16 0.203
LD (m) 0.535 6 0.047 0.514 6 0.053 0.562 6 0.049 0.512 6 0.080 16 0.326
70–79% 1RM
ACV (m·s21) 0.58 6 0.08 0.50 6 0.08† 0.57 6 0.11 0.46 6 0.07† 14 0.390
PCV (m·s21) 1.01 6 0.13 0.85 6 0.19† 1.11 6 0.23 0.83 6 0.21† 14 0.586
LD (m) 0.559 6 0.044 0.539 6 0.049 0.571 6 0.059 0.517 6 0.079† 14 0.776
60–69% 1RM
ACV (m·s21) 0.64 6 0.10 0.56 6 0.08 0.67 6 0.13 0.56 6 0.07† 9 0.299
PCV (m·s21) 1.06 6 0.19 0.93 6 0.26 1.15 6 0.28 0.95 6 0.21 9 0.213
LD (m) 0.568 6 0.057 0.536 6 0.036 0.592 6 0.049 0.469 6 0.051† 9 0.650
50–59% 1RM
ACV (m·s21) 0.71 6 0.10 0.65 6 0.10 0.73 6 0.11 0.65 6 0.13 6 0.683
PCV (m·s21) 1.13 6 0.18 1.04 6 0.15 1.22 6 0.21 1.01 6 0.11 6 0.755
LD (m) 0.566 6 0.056 0.551 6 0.052 0.567 6 0.048 0.575 6 0.074 6 0.672
40–49% 1RM
ACV (m·s21) 0.81 6 0.12 0.67 6 0.08† 0.83 6 0.13 0.66 6 0.13† 13 0.805
PCV (m·s21) 1.26 6 0.28 1.00 6 0.12† 1.34 6 0.26 1.06 6 0.23† 13 0.327
LD (m) 0.575 6 0.058 0.546 6 0.043 0.594 6 0.037 0.518 6 0.066† 13 0.988
30–39% 1RM
ACV (m·s21) 0.82 6 0.13 0.71 6 0.10 0.92 6 0.18 0.62 6 0.07† 12 0.548
PCV (m·s21) 1.27 6 0.27 1.05 6 0.14 1.47 6 0.25 1.03 6 0.18† 12 0.060
LD (m) 0.595 6 0.035 0.561 6 0.039 0.596 6 0.074 0.497 6 0.043† 12 0.484
*1RM 5 1 repetition maximum; ACV 5 average concentric velocity; PCV 5 peak concentric velocity; LD 5 linear displacement.
†p , 0.05 vs. men.
Squat and Deadlift Kinematics (2019) 33:12 | www.nsca.com
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www.nsca.com
50–59%, 60–69%, 70–79%, 80–89%, and 90–99% 1RM.
There were no differences in actual %1RM between the lifts in
any category, and the range of actual %1RM was evenly dis-
tributed within each category. Kinematic data corresponding to
each category were compared between each lift (FS vs. BS and CD
vs. SD). Because subjects completed between 1 and 5 1RM
attempts and may have over- or under-estimated their actual
1RM, this led to a different sample size for each category.
Statistical Analyses
All data were checked for normality using the Shapiro-Wilk test.
When variables were normally distributed, paired-samples t-tests
(2-tailed) were used to compare ACV, PCV, and LD between the
FS and BS and between the SD and CD at each relative load; when
variables were not normally distributed, Wilcoxon signed-rank
tests were used for analysis. A sample size of 13 (N 5 13) would
provide 80% power to correctly reject the null hypothesis, as-
suming a mean difference of 0.06 m·s21 between 2 lifts at a rela-
tive load with a SD of 0.08 m·s21 (effect size of 0.75). All analyses
used an alpha level of 0.05. Independent-samples t-tests were used
to compare men and women in subject characteristics (2-tailed t-
tests) and for all kinematic variables (1-tailed t-tests). Pearson’s
product-moment correlations were used to examine relationships
between demographic variables, relative strength levels, and ki-
nematics measured (ACV, PCV, and LD) at the 1RM for each lift.
In addition, correlations were used to compare the relationships
between kinematic variables at the 1RM and at 80–89% 1RM for
each lift because this was the load at which we had the largest
sample size other than the 1RM. Finally, correlations between
kinematic variables for the FS and BS and for the CD and SD were
examined at each relative load. All data are presented as mean 6
SD. Statistical analyses were performed using JASP v0.9.0.1
(Amsterdam, the Netherlands).
Results
Table 2 presents the data for the FS and BS. Subjects had more
experience (greater training frequency and training age) as well as
a greater 1RM for the BS compared with the FS. However, no
Table 3
Comparison between the conventional and sumo deadlift.*
Conventional deadlift Sumo deadlift
N Lift comparison pMen Women Men Women
Training age (y) 4.2 6 3.3 5.0 6 2.4 2.3 6 2.9 2.8 6 2.9 24 ,0.001
Frequency (d·wk21) 0.9 6 0.7 1.0 6 0.8 0.5 6 0.7 0.5 6 0.7 24 0.004
One year of experience with exercise (n) 15 9 9 8
1RM (kg) 158.3 6 38.3 91.7 6 11.2† 151.7 6 38.3 90.0 6 14.4† 24 0.032
Relative 1RM 1.90 6 0.30 1.37 6 0.21† 1.81 6 0.36 1.34 6 0.21† 24 0.032
1RM
ACV (m·s21) 0.23 6 0.05 0.29 6 0.07† 0.24 6 0.08 0.27 6 0.11 24 0.943
PCV (m·s21) 0.45 6 0.08 0.57 6 0.09† 0.51 6 0.56 0.56 6 0.19 24 0.301
LD (m) 0.549 6 0.030 0.502 6 0.052† 0.474 6 0.050 0.449 6 0.041 24 ,0.001
90–99% 1RM
ACV (m·s21) 0.29 6 0.06 0.35 6 0.08† 0.26 6 0.06 0.28 6 0.03 16 0.068
PCV (m·s21) 0.52 6 0.08 0.71 6 0.11† 0.53 6 0.12 0.53 6 0.19 16 1.000
LD (m) 0.547 6 0.033 0.512 6 0.393† 0.480 6 0.048 0.445 6 0.038 16 ,0.001
80–89% 1RM
ACV (m·s21) 0.41 6 0.07 0.37 6 0.06 0.35 6 0.08 0.34 6 0.06 19 0.008
PCV (m·s21) 0.73 6 0.16 0.79 6 0.07 0.69 6 0.15 0.77 6 0.18 19 0.307
LD (m) 0.571 6 0.034 0.515 6 0.029† 0.498 6 0.055 0.454 6 0.057† 19 ,0.001
70–79% 1RM
ACV (m·s21) 0.48 6 0.05 0.44 6 0.08 0.43 6 0.08 0.43 6 0.12 17 0.026
PCV (m·s21) 0.86 6 0.12 0.91 6 0.13 0.83 6 0.12 0.87 6 0.20 17 0.243
LD (m) 0.577 6 0.037 0.514 6 0.043† 0.502 6 0.058 0.470 6 0.034 17 ,0.001
60–69% 1RM
ACV (m·s21) 0.56 6 0.10 0.52 6 0.08 0.58 6 0.10 0.47 6 0.07† 15 0.764
PCV (m·s21) 1.00 6 0.16 0.97 6 0.11 1.07 6 0.16 1.02 6 0.13 15 0.533
LD (m) 0.567 6 0.054 0.507 6 0.037† 0.540 6 0.069 0.468 6 0.036† 15 0.015
50–59% 1RM
ACV (m·s21) 0.66 6 0.10 0.69 6 0.09 0.55 6 0.11 0.57 6 0.05 11 0.064
PCV (m·s21) 1.17 6 0.15 1.24 6 0.11 1.00 6 0.17 1.04 6 0.12 11 0.016
LD (m) 0.586 6 0.045 0.543 6 0.031† 0.515 6 0.066 0.487 6 0.041 11 0.004
40–49% 1RM
ACV (m·s21) 0.76 6 0.10 0.72 6 0.08 0.68 6 0.08 0.63 6 0.08 16 ,0.001
PCV (m·s21) 1.31 6 0.18 1.25 6 0.13 1.17 6 0.19 1.19 6 0.14 16 0.002
LD (m) 0.585 6 0.050 0.540 6 0.037† 0.549 6 0.102 0.481 6 0.029 16 0.008
30–39% 1RM
ACV (m·s21) 0.76 6 0.11 0.68 6 0.08 0.78 6 0.15 0.71 6 0.10 13 0.556
PCV (m·s21) 1.33 6 0.21 1.16 6 0.21 1.39 6 0.27 1.23 6 0.16 13 0.429
LD (m) 0.593 6 0.053 0.542 6 0.019† 0.556 6 0.070 0.504 6 0.045 13 ,0.001
*1RM 5 1 repetition maximum; ACV 5 average concentric velocity; PCV 5 peak concentric velocity; LD 5 linear displacement.
†p , 0.05 vs. men.
Squat and Deadlift Kinematics (2019) 33:12
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significant differences were noted in ACV or LD between the FS
and BS at the 1RM or any percentage of the 1RM (Table 2). For
the BS, ACV and PCV values were lower for women compared
with men at the same relative loads except at the 1RM and at
50–50% 1RM. For the FS, ACV and PCV were lower for women
compared with men only at loads of 40–49% and 70–79% 1RM.
Table 3 presents the data for the CD and SD. Subjects’ had
more experience (greater training frequency and training age) as
well as a greater 1RM for the CD compared with the SD. Greater
LD was observed for the CD compared with the SD at all loads.
Greater ACV was observed at some submaximal loads (40–49%,
70–79%, and 80–89% 1RM) for the CD compared with the SD
(Table 3). For the CD, sex differences in LD were observed across
all loads with men having greater LD compared with women; men
also had lower ACV values at 90–99% 1RM and at the 1RM
compared with women. For the SD, LD was greater for men
compared with women at loads of 80–89% and 60–69% 1RM,
with men showing greater ACV values than women at 60–69%
1RM as well.
Correlations between kinematic variables recorded at the
1RM, subject characteristics, and kinematics recorded at
80–89% 1RM are reported in Table 4. Notable, body mass
showed a strong, positive correlation to 1RM ACV and PCV for
the BS but not any of the other lifts. Average concentric velocity
values at the 1RM and at 80–89% 1RM were strongly related for
the FS, moderately related for the BS and SD, and weakly related
for the CD. Peak concentric velocity values at the 1RM and at
80–89% 1RM were strongly related for the FS, BS, and SD and
moderately related for the CD. Linear displacement values at the
1RM and at 80–89% 1RM were strongly related for the FS, BS,
and CD and very strongly related for the SD. For the SD and CD,
1RM ACV was inversely related to relative strength, whereas the
correlations between 1RM ACV and relative strength were not as
strong for the FS or BS.
Correlations between kinematic variables for the 2 types of
squats and 2 types of deadlifts at each relative load are shown in
Table 5. Notably, ACV values for the FS and BS showed weak
correlations at high loads (.80% 1RM) but moderate-to-strong
relationships at lower loads (,80% 1RM). Average concentric
velocity values for the SD and CD showed weak correlations at
most loads despite moderate to very strong correlations between
LD at all loads.
Discussion
The primary findings of this study were as follows: (a) although
FS and BS kinematics at the same relative load are not statistically
different, ACV values between the FS and BS are weakly related at
high (.80% 1RM) loads; (b) LD and ACV values differ between
the CD and SD at the same relative load; (c) ACV values are
weakly related between the CD and SD at most loads; (d) women
generally exhibit lower velocities than men at the same relative
load; and (e) kinematics at high loads (80–89% 1RM) and
maximal loads (1RM) are strongly correlated for the FS, mod-
erately correlated for the BS and SD, and weakly to moderately
correlated for the CD. These findings have implications for those
using ACV for prescribing training loads.
Similar to another study comparing the load-velocity profile
between the FS and BS (20), kinematics at a given load were not
statistically different between the FS and BS. However, examining
the relationships between FS and BS kinematics at each relative
load, it seems ACV values are not necessarily the same for the FS
Table 4
Correlations between select variables for each lift.*
1RM ACV 1RM PVC 1RM LD
FS
Body mass 0.077 20.009 20.272
Height 0.114 20.236 20.029
Relative strength 20.120 20.149 20.271
80–89% 1RM ACV 0.774† 0.270 0.307
80–89% 1RM PCV 0.522† 0.637† 0.185
80–89% 1RM LD 0.386 0.078 0.638†
BS
Body mass 0.654† 0.485† 0.161
Height 0.433† 0.185 0.560†
Relative strength 0.225 0.495† 20.072
80–89% 1RM ACV 0.587† 0.194 0.294
80–89% 1RM PCV 0.314 0.606† 0.174
80–89% 1RM LD 0.198 20.064 0.723†
CD
Body mass 20.260 20.326 0.437†
Height 20.402 20.589† 0.618†
Relative strength 20.681† 20.631† 0.153
80–89% 1RM ACV 0.362 0.288 0.319
80–89% 1RM PCV 0.457† 0.533† 0.027
80–89% 1RM LD 0.068 20.044 0.774†
SD
Body mass 0.214 20.010 0.153
Height 0.094 20.011 0.453†
Relative strength 20.424† 20.446† 20.161
80–89% 1RM ACV 0.547† 0.483† 0.266
80–89% 1RM PCV 0.689† 0.692† 0.264
80–89% 1RM LD 0.377 0.316 0.827†
*1RM 5 1 repetition maximum; ACV 5 average concentric velocity; PCV 5 peak concentric velocity;
LD 5 linear displacement; FS 5 front squat; BS 5 back squat.
†Correlational significant at p , 0.05.
Table 5
Correlations between 2 styles of each lift at each relative load.*
30–39% 40–49% 50–59% 60–69% 70–79% 80–89% 90–99% 1RM
Squat
ACV 0.522 0.698† 0.584 0.707† 0.699† 20.312 20.276 0.303
PCV 0.621† 0.834† 0.696 0.624 0.719† 20.185 0.609 0.463†
LD 0.601† 20.004 20.151 0.057 20.361 20.005 20.309 20.012
Deadlift
ACV 0.245 0.361 0.010 0.030 0.307 0.414 0.230 0.433†
PCV 0.489 0.275 0.148 20.338 0.060 0.525† 0.188 0.327
LD 0.903† 0.570† 0.689† 0.826† 0.694† 0.629† 0.575† 0.586†
*1RM 5 1 repetition maximum; ACV 5 average concentric velocity; PCV 5 peak concentric velocity; LD 5 linear displacement.
†Correlation is significant at p , 0.05.
Squat and Deadlift Kinematics (2019) 33:12 | www.nsca.com
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and BS at high (.80% 1RM) loads. This is likely due to …
