Some of us like working out in the gym using machines – and that’s fine! There’s a range of benefits associated with using gym machines, and if it’s what works for you, that’s great. But I want to share just a few of the reasons I love to get clients performing free weight exercises.
1) Greater Muscle Activation
In the gym, you might interchangeably use a free weight squat and a leg press to work out the quadriceps and glute muscles, or free weight bench press instead of a bench press machine to work the pectorals and triceps. However, unlike the leg press or the bench machine, a squat and a free weight bench press require balance, and therefore a substantial amount of engagement of stabilising muscles (1,2). Research has shown that free weight exercises result in greater muscle activation than machine exercise. This means that overall, more muscle mass is working during free weight exercise than during similar machine exercise.
2) Greater Hormonal Response
Exercises involving greater muscle activation can result in a larger hormonal response (3). Testosterone and growth hormone are two important hormones for promoting muscle strength and growth increases. Both the squat and the leg press have been found to increase these hormone levels in the blood after being performed. However, the squat was found to increase circulating testosterone and growth hormone to a significantly higher level that the leg press. The higher increase in testosterone and growth hormone with free weight exercises could lead to greater muscle growth than with machine exercises. Studies have also shown that the increased growth hormone due to exercise may have an even greater strengthening effect on our tendons (4).
(1) EE Schick Affiliation: Exercise Physiology Laboratory, Department of Kinesiology, California State University et al. (2010). A comparison of muscle activation between a Smith machine and free weight bench press. Journal of strength and conditioning research / National Strength & Conditioning Association, 24(3), 779-84.
(2) S Schwanbeck Affiliation, College of Kinesiology, University of Saskatchewan, et al. (2009). A comparison of free weight squat to Smith machine squat usin electromyography. Journal of strength and conditioning research / National Strength & Conditioning Association, 23(9), 2588-91.
(3) Shaner et al. (2014). The Acute Hormonal Response to Free Weight and Machine Weight Resistance Exercise. Journal of Strength and Conditioning Research, 28(4), 1032-1040.
(4) K M Heinemeier Affiliation: Institute of Sports Medicine, Bispebjerg Hospital et al. (2012). GH/IGF – I axis and matrix adaptation of the musculotendinous tissue to exercise in humans. Scandinavian Journal of Medicine and Science in Sports, 22(4), e1-e7.