ARE SQUATS ARE THE KING OF HAMSTRING GROWTH?

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DO SQUATS WORK HAMSTRINGS SUMMARY

•      Squats are great for quad growth but do not increase hamstring growth.
•       The depth has a major determination of which muscles will grow. Shallow or half range of motion will emphasize the quads, but a deep squat is needed to maximize the growth of the glutes.
•       Hamstring curls, Stiff-legged deadlifts, seated leg curls, and Nordic hamstring curls should all be included with the squat to maximize the growth of the hamstrings.

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DO BACK SQUATS WORK HAMSTRINGS?

For the last decade, it’s been stated that the squat increases muscle growth of the quadriceps, hamstrings, and glutes. Several studies have shown that the squat results in hamstring activation. The squat has been classified as a moderate level of muscle activation; hamstring activation increases up to 30.24%. (1)  Many people will often imply that because an exercise has greater muscle “activation,” it leads to greater muscle growth. Caution should be emphasized by extrapolating “muscle activation” studies to muscle growth. There are no longitudinal studies to suggest increased “muscle activation” or increased EMG is predictive of muscle growth.

For example, Jenkins et al. (2015) conducted an EMG study on leg extensions performed to muscular failure with a heavy weight (3 sets of 80% 1 RM) or light weight (3 sets of 30% 1 RM). There was greater muscle activation in the heavy weight group than the light weight group but muscle growth increased the same in both groups. (2) It’s been well documented that muscle activation is a poor method of predicting long-term muscle growth. (3) Using muscle activation for an exercise cannot be used to imply greater muscle growth.

STUDIES ON HAMSTRING MUSCLE GROWTH

A recent review in the Strength and Conditioning Journal titled A Brief Review on the Effects of the Squat Exercise on Lower-Limb Muscle Hypertrophy provided a comprehensive list of all the studies examining muscle growth of all the different muscle groups during the squat. (4)

RECTUS FEMORIS (MIDDLE AREA OF THE QUAD): Most of the studies demonstrate a poor growth of the rectus femoris during the squat. A much better exercise to use would be the leg extension.

HAMSTRINGS (BACK OF THE LEGS): Most studies show little to no muscle growth during the back squat. Six studies found zero muscle growth of the hamstrings during several weeks of squat training. Other exercises must be included to maximize hamstring growth, such as the leg curl, seated leg curls, or Nordic Curls.

VASTUS LATERALIS (MUSCLE ON THE SIDE OF THE QUAD): Most studies have found large increases in the vastus lateralis growth with the squat. Performing a half squat can result in greater activation of the quads but reduced activation of the glutes.

GLUTEUS MAXIMUS (GLUTES): Muscle growth for the glutes depends on how deep you squat. Squatting with half reps results in less glute muscle growth than deep squats.

CALVES: No effect on muscle growth of the calves was noted during the squat. Include exercises like standing, and seated calf raises to increase muscle growth of the calves.

SQUATS DON’T INCREASE HAMSTRING GROWTH

The squat is a great exercise for the legs, but it depends on several factors, such as how deep you are going down will determine which muscles are optimized. Doing a half-range of motion will cause greater activation of the quads with less activation of the glutes. Whereas a deeper squat, there is more glute growth. The studies overwhelmingly show that the hamstrings or calves do not increase in muscle size during squats. To optimize growth, other exercises need to be performed for the calves and hamstrings to increase muscle growth.

 

REFERENCES

1. Llurda-Almuzara L, Labata-Lezaun N, López-de-Celis C, Aiguadé-Aiguadé R, Romaní-S S, Rodríguez-Sanz J, et al. Biceps Femoris Activation during Hamstring Strength Exercises: A Systematic Review. International journal of environmental research and public health. 2021;18(16):8733.

2.         Jenkins ND, Housh TJ, Bergstrom HC, Cochrane KC, Hill EC, Smith CM, et al. Muscle activation during three sets to failure at 80 vs. 30% 1RM resistance exercise. Eur J Appl Physiol. 2015;115(11):2335-47.

3.         Vigotsky AD, Beardsley C, Contreras B, Steele J, Ogborn D, Phillips SM. Greater electromyographic responses do not imply greater motor unit recruitment, and ‘hypertrophic potential’ cannot be inferred. J Strength Cond Res. 2017;31(1):e1-e4.

4.         Ribeiro AS, Santos ED, Nunes JP, Nascimento MA, Graça Á, Bezerra ES, et al. A Brief Review on the Effects of the Squat Exercise on Lower-Limb Muscle Hypertrophy. Strength & Conditioning Journal. 9000.

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