Effects of technique variations on knee biomechanics during the squat and leg press.

  title={Effects of technique variations on knee biomechanics during the squat and leg press.},
  author={Rafael F. Escamilla and Glenn S. Fleisig and Nigel Zheng and Jeffrey Evan Lander and Steven W. Barrentine and James R. Andrews and Brian W. Bergemann and C. T. Moorman},
  journal={Medicine and science in sports and exercise},
  volume={33 9},
PURPOSE The specific aim of this project was to quantify knee forces and muscle activity while performing squat and leg press exercises with technique variations. METHODS Ten experienced male lifters performed the squat, a high foot placement leg press (LPH), and a low foot placement leg press (LPL) employing a wide stance (WS), narrow stance (NS), and two foot angle positions (feet straight and feet turned out 30 degrees ). RESULTS No differences were found in muscle activity or knee… 

Patellofemoral joint force and stress during the wall squat and one-leg squat.

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Comparison of Joint and Muscle Biomechanics in Maximal Flywheel Squat and Leg Press

The finding of a propensity to perform leg press at deeper knee angle than squat may suggest that leg press is the preferable leg-extension resistance exercise, both from a training efficacy and injury risk perspective.

Investigating the role of foot placement on the muscular forces of knee extensors in horizontal leg press: A static optimization approach

A 3-DOF musculoskeletal model of lower-extremity was developed and a significant difference was showed between the obtained muscle forces for knee extensors in each technique, suggesting that if strengthening the knee Extensors is of desire, LPH technique is not the correct format for performing the exercise.

How to squat? Effects of various stance widths, foot placement angles and level of experience on knee, hip and trunk motion and loading

Suitable stance width and foot placement angles should be chosen according to the targeted joint moments in order to avoid injury.

Knee biomechanics of the dynamic squat exercise.

  • R. Escamilla
  • Medicine, Biology
    Medicine and science in sports and exercise
  • 2001
The squat was shown to be an effective exercise to employ during cruciate ligament or patellofemoral rehabilitation, and can enhance stability if performed correctly.

Effects of External Load on Sagittal and Frontal Plane Lower Extremity Biomechanics During Back Squats.

The results indicate that submaximum squats performed at increased velocities can provide similar moments at the ankle and knee, but not hip, as maximal loads and significant emphasis on hip strength is necessary for heavy back squats.

A Biomechanical Comparison of Back and Front Squats in Healthy Trained Individuals

The results suggest that front squats may be advantageous compared with back squats for individuals with knee problems such as meniscus tears, and for long-term joint health.

Alterations in Three-dimensional Knee Kinematics and Kinetics during Neutral, Squeeze and Outward Squat

A neutral position is recommended to perform the squat exercise, while the squeeze squat and outward squat might contribute to the occurrence of joint pathologies.

Effects of front and back squat techniques on patellofemoral joint kinetics in males

The back squat appears to place lifters at greater risk from injury, and it may be prudent therefore for lifters who are predisposed to patellofemoral pain syndrome to utilize the front squat in their training.



Stance width and bar load effects on leg muscle activity during the parallel squat.

The results suggest that stance width does not cause isolation within the quadriceps but does influence muscle activity on the medial thigh and buttocks.

Effect of Foot Position on the Electromyographical Activity of the Superficial Quadriceps Muscles During the Parallel Squat and Knee Extension

Bipolar surface electrodes placed on the bellies of the v. lateralis and v. medialis revealed no significant differences in electrical activity for any muscle due to changes in foot position during the squat, however, LR produced a significantly greater mean rmsEMG than the other foot positions across all muscles.

Comparison of Intersegmental Tibiofemoral Joint Forces and Muscle Activity During Various Closed Kinetic Chain Exercises

The results showed that the mean tibiofemoral shear force was posterior (tibial force on femur) throughout the cycle of all three exercises, indicating that the potential loading on the injured or reconstructed anterior cruciate ligament is not significant.

Biomechanics of the knee during closed kinetic chain and open kinetic chain exercises.

This study quantified knee forces and muscle activity in CKCE and OKCE to help in choosing appropriate exercises for rehabilitation and training.

A Comparison of Tibiofemoral Joint Forces and Electromyographic Activit During Open and Closed Kinetic Chain Exercises

Electromyographic data indicated greater hamstring and quadriceps muscle co-contraction during the squat compared with the other two exercises, and significant differ ences in tibiofemoral forces and muscle activity be tween the two closed kinetic chain exercises.

EMG analysis of lower extremity muscle recruitment patterns during an unloaded squat.

Results revealed minimal hamstring activity as compared with quadriceps activity during an unloaded squat in healthy subjects, and this low level of hamstring EMG activity was interpreted to reflect the low demand placed on the hamstring muscles to counter anterior shear forces acting at the proximal tibia.

A Comparison of Quadriceps Electromyographic Activity With the Position of the Foot During the Parallel Squat

The practice of adopting foot rotation to selectively strengthen individual muscles of the quadriceps group was not supported by this study, which involved smaller, more readily adopted, and comfortable levels of foot rotation than did those previously investigated.

Joint moments of force and quadriceps muscle activity during squatting exercise

Knee joint load can be limited by doing parallel instead of deep squats and that this will not decrease quadriceps muscle activity, and to limit hip moment, the squat should not be deeper than 90°.

Quadriceps EMG/force relationship in knee extension and leg press.

Data suggest a nonuniform recruitment pattern among the three superficial QF muscles and surface EMG recordings from VL to be most reliable in predicting force output in isometric multi-joint leg press exercises.

A three-dimensional biomechanical analysis of the squat during varying stance widths.

A 3-D biomechanical analysis of the squat is more accurate than a 2-D analysis, especially during the WS, and knee and hip moments were greater during theWS compared with the NS.