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Hi- and Low-bar Squatting

Wretenberg et al (1) examined the  differences between high-bar (used by Olympic lifters in  training) and low-bar (used by powerlifters in training  and competition) squatting techniques.  They  examined differences in moments of force at the knee and  hip joints and EMG activity of the vastus lateralis,  rectus femoris, and biceps femoris.  8 Swedish  national class Olympic weightlifters and 6 Swedish  national class powerlifters were used in the study.   Weightlifters performed high-bar squats and  powerlifters performed low-bar squats;  each group  of lifters did not perform both types due to lack of  skill in the technique that did not correspond with their  particular sport.  In both groups, 2 depths of  squatting were examined:  parallel (posterior border  of hamstring parallel with ground) and full (knees  maximally flexed).  All subjects lifted 65% of their  all-time 1 RM.  Motion analyses were performed using  a video camera, with skin markers placed at the trunk,  hip, knee, ankle, and foot.  Coordinates of the  markers were established using a video position analyzer.   Ground reaction forces were measured using a  Kistler force platform;  vertical, anteroposterior,  and lateral forces were measured during the ascent phase.   Knee and hip joint moments were calculated using a  computer program and the data from the markers and the  force platform.  EMG activity was related to a  static reference position to compare muscle activity of  both types of squats.  A parametric t-test was used  as the statistical analysis.

RESULTS:  Powerlifters placed more  load on the hip joint while weightlifters had an equal  distribution of the load between the knee joint and hip  joint.  maximum moments at the hip joint were  significantly higher for the powerlifters as compared to  the Olympic lifters (324 Nm deep and 309 Nm parallel vs.  230 Nm deep and 216 Nm parallel).  In contrast,  maximum moments at the knee joint were significantly  higher in the Olympic lifters (139 Nm deep and 92 Nm  parallel for powerlifters vs. 191 Nm deep and 131 Nm  parallel for Olympic lifters), despite the powerlifters  having heavier bodyweights and lifting heavier loads.   Patello-femoral compression force was significantly  higher in the weightlifters as compared to the  powerlifters (4700 N vs. 3300 N).  Powerlifters  showed greater EMG in all measured muscles, although only  the rectus femoris was found to reach statistical  significance.

IMPLICATIONS:  Low-bar squatting  techniques involve greater hip flexion and thus greater  hip moments of force, while in the high-bar technique the  load is more equally distributed.  the greater  amount of hip flexion allows the lifter to balance the  bar closer to the knee, reducing the moment arm between  the knee and the weight.  this reduces knee moment  forces and the patello-femoral compression force.  This  also results in greater reliance in the hip and back  musculature, allowing the individual to lift more weight,  which is crucial to powerlifters.

An interesting outcome of this study was  the slightly higher muscle activity found in the knee  extensors of the powerlifters, despite the weightlifters  having higher knee moments.  The authors'  explanation was that the calculated moments were net  moments;  the muscular co-contraction of  antagonistic muscle groups was not included in the  calculations.  the greater hip extension needed  during the ascent phase of the low-bar squat, along with  the greater need for compensatory ankle plantar flexion,  would result in greater hamstring and gastrocnemius  activity during the lift.  The increase in activity  of these muscles would result in an increased knee  extensor co-contraction, resulting in high knee extensor  EMG activity despite low moments of force at the knee.

The higher knee moments of the high-bar  squat indicates that a low-bar squat would be beneficial  in knee rehabilitation situations.  In contrast, the  higher hip moments of the low-bar squat indicates that a  high-bar squat would be beneficial in hip rehabilitation  situations.

1.  Wretenberg, P., Y. Feng, and U.P.  Arborelius.  High- and low-bar squatting techniques  during weight-training.  Med. Sci. Sports Exerc.   28(2):218-224.  1996.