tp_88
2007-03-17, 02:09
The BNBF Squatting Experiment: Does squatting involve the same amount of muscular activation as leg press or hack squatting?
In order to establish the most effective resistance exercise for quadricep development the BNBF sanctioned a scientific investigation, collaborating with Napier Universities sports science research department. The investigation was prompted by varying opinions on the optimal resistance exercise to induce muscular hypertrophy in the quadriceps of body builders. Many body builders and trained coaches believe that conventional squatting is ineffective at producing large quantities of muscular hypertrophy when compared to such exercises as hack squatting and leg pressing. In order to establish whether these views had any scientific grounding, a series of controlled experiments were undertaken in a private resistance training facility.
Three trained body builders with at least five years resistance training experience were recruited for this micro study. Each of the subjects had refrained from leg training 2 days prior to the commencement of the experimental protocols to ensure neuromuscular fatigue and myofibril damage had no influence on results. The testing was separated into three phases, squatting, leg press and hack squatting conducted in randomised order to eliminate any potential influence of fatigue on the results as previously stated. The exercises were as follows; wide and normal stance squatting at 3/4 depth and 90 degrees (parallel), wide and close stance leg press and finally close and wide stance hack squats. Each subject performed 3 repetitions of each exercise at 90% of there 1 repetition maximal established 1 week prior to the testing session. Five minutes recovery was given between trials.
Muscular electromyography was used to measure muscular activation during each trial in millivolts. A four channel EMG was attached to the Vastus Medialis, Rectus Femoris and Vastus Lateralis of the right quadriceps and also the Biceps Femoris of the Hamstrings. The average of the three repetitions was taken as the result for each exercise. After the completion of the testing the results were collated and subsequently analysed.
The results demonstrated that shallow ¾ squatting (68º knee flexion), both wide and shallow stances, produced the greatest amount of quadriceps stimulation. Shallow squatting elicited 20% more muscular activation throughout the three quadricep muscles measured compared to full 90º squats. This is likely due to the constant load applied to the quadriceps during shallow squats. During full squats the load is assisted by the gluteus and hamstring muscles during the concentric drive phase of the action which reduces the load and subsequent activation of the quadriceps. This was evident from the EMG results, with the Biceps Femoris muscle being stimulated 50% more during full squats compared to shallow squats.
Hack squatting and leg press both produced similar muscular activation patterns for those measured during close and wide stances. However quadriceps activation was 30% and 15% less when compared with shallow squatting and normal squatting respectively. Biceps Femoris activation however was significantly reduced during leg press compared with all other exercises. Activation of the Biceps Femoris muscle was 18%, 200% and 450% greater for hack squatting, shallow squats and full squats respectively compared with leg press.
These results suggests that leg press isolates the quadriceps muscles better than squatting or hack squatting. However in relative terms, squatting shallow and to a lesser extent full squatting, produces more muscular activation of the quadriceps in relation to the relative load applied compared to any of the other exercises tested. Squatting also utilised more of the biceps femoris (hamstring muscle) than leg press or hack squatting as previously stated. This translates into a more complete utilisation of the leg muscles during each contraction. Also full (90º) squats elicits the utilisation of the gluteuls which again provides a more complete leg workout compared to hack squatting or leg press. Therefore squatting should provide more muscular stimulation and subsequent development compared to other exercises. A greater level of muscular activation results in a larger percentage of the muscle fibres being utilised during the activity allowing for more muscular damage to result. As the body is an over compensatory system, if enough recovery is given the body will not only repair the myofibril damage but muscle hypertrophy will result. If this form of training is continued with a constant progression of the imposed load, the result will be larger stronger muscles which is the ultimate goal of the body builder.
Accordingly squatting to 68º and 90º of knee flexion should produced greater gains in muscle mass and strength in the quadriceps compared with leg press and hack squats. However squatting below parallel will noticeably shift the implied load away from the quadriceps and induce greater activity within the hamstrings and gluteuls. This may reduce quadricep development. However squatting below 90 degrees will shift the emphasis from hamstrings to gluteals. Accordingly squatting to 85º will likely induce the optimal ratio between quadricep and hamstring / gluteul development in one exercise and result in greater overall leg development compared to leg press or hack squats. Therefore squatting, preferably to 85º should be an essential part of any bodybuilders leg workouts.
Written by Scott Macrae,BNBF Scientific development officer.
Bsc Honours Sports Science.
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In order to establish the most effective resistance exercise for quadricep development the BNBF sanctioned a scientific investigation, collaborating with Napier Universities sports science research department. The investigation was prompted by varying opinions on the optimal resistance exercise to induce muscular hypertrophy in the quadriceps of body builders. Many body builders and trained coaches believe that conventional squatting is ineffective at producing large quantities of muscular hypertrophy when compared to such exercises as hack squatting and leg pressing. In order to establish whether these views had any scientific grounding, a series of controlled experiments were undertaken in a private resistance training facility.
Three trained body builders with at least five years resistance training experience were recruited for this micro study. Each of the subjects had refrained from leg training 2 days prior to the commencement of the experimental protocols to ensure neuromuscular fatigue and myofibril damage had no influence on results. The testing was separated into three phases, squatting, leg press and hack squatting conducted in randomised order to eliminate any potential influence of fatigue on the results as previously stated. The exercises were as follows; wide and normal stance squatting at 3/4 depth and 90 degrees (parallel), wide and close stance leg press and finally close and wide stance hack squats. Each subject performed 3 repetitions of each exercise at 90% of there 1 repetition maximal established 1 week prior to the testing session. Five minutes recovery was given between trials.
Muscular electromyography was used to measure muscular activation during each trial in millivolts. A four channel EMG was attached to the Vastus Medialis, Rectus Femoris and Vastus Lateralis of the right quadriceps and also the Biceps Femoris of the Hamstrings. The average of the three repetitions was taken as the result for each exercise. After the completion of the testing the results were collated and subsequently analysed.
The results demonstrated that shallow ¾ squatting (68º knee flexion), both wide and shallow stances, produced the greatest amount of quadriceps stimulation. Shallow squatting elicited 20% more muscular activation throughout the three quadricep muscles measured compared to full 90º squats. This is likely due to the constant load applied to the quadriceps during shallow squats. During full squats the load is assisted by the gluteus and hamstring muscles during the concentric drive phase of the action which reduces the load and subsequent activation of the quadriceps. This was evident from the EMG results, with the Biceps Femoris muscle being stimulated 50% more during full squats compared to shallow squats.
Hack squatting and leg press both produced similar muscular activation patterns for those measured during close and wide stances. However quadriceps activation was 30% and 15% less when compared with shallow squatting and normal squatting respectively. Biceps Femoris activation however was significantly reduced during leg press compared with all other exercises. Activation of the Biceps Femoris muscle was 18%, 200% and 450% greater for hack squatting, shallow squats and full squats respectively compared with leg press.
These results suggests that leg press isolates the quadriceps muscles better than squatting or hack squatting. However in relative terms, squatting shallow and to a lesser extent full squatting, produces more muscular activation of the quadriceps in relation to the relative load applied compared to any of the other exercises tested. Squatting also utilised more of the biceps femoris (hamstring muscle) than leg press or hack squatting as previously stated. This translates into a more complete utilisation of the leg muscles during each contraction. Also full (90º) squats elicits the utilisation of the gluteuls which again provides a more complete leg workout compared to hack squatting or leg press. Therefore squatting should provide more muscular stimulation and subsequent development compared to other exercises. A greater level of muscular activation results in a larger percentage of the muscle fibres being utilised during the activity allowing for more muscular damage to result. As the body is an over compensatory system, if enough recovery is given the body will not only repair the myofibril damage but muscle hypertrophy will result. If this form of training is continued with a constant progression of the imposed load, the result will be larger stronger muscles which is the ultimate goal of the body builder.
Accordingly squatting to 68º and 90º of knee flexion should produced greater gains in muscle mass and strength in the quadriceps compared with leg press and hack squats. However squatting below parallel will noticeably shift the implied load away from the quadriceps and induce greater activity within the hamstrings and gluteuls. This may reduce quadricep development. However squatting below 90 degrees will shift the emphasis from hamstrings to gluteals. Accordingly squatting to 85º will likely induce the optimal ratio between quadricep and hamstring / gluteul development in one exercise and result in greater overall leg development compared to leg press or hack squats. Therefore squatting, preferably to 85º should be an essential part of any bodybuilders leg workouts.
Written by Scott Macrae,BNBF Scientific development officer.
Bsc Honours Sports Science.
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