Squats create a stronger anabolic stimulus in the body than equally heavy sets on a leg press machine. Sports scientists from the University of North Texas report on this in the Journal of Strength and Conditioning Research. The Texans discovered that bodybuilders synthesise more growth hormone and testosterone after a squat session than after a session on a leg press machine.
Squats create a stronger anabolic stimulus in the body than equally heavy sets on a leg press machine.
Sports scientists from the University of North Texas report on this in the Journal of Strength and Conditioning Research. The Texans discovered that bodybuilders synthesise more growth hormone and testosterone after a squat session than after a session on a leg press machine.
Strength training done with bars and dumbbells produces better results than using machines. Training with free weights is also better for physical coordination and stimulates more muscle groups than training with machines does. What’s more, the movements you make with free weights tend to be more natural and therefore injuries are less likely to happen.
Whether training on machines or with free weights also has different physiological effects is not known. That’s why the Texans did an experiment with ten well-trained male strength athletes – average age 25 years – who trained their legs on two occasions: on one occasion doing squats and on another using the leg press. Both times the athletes did 6 sets of 10 reps. For each training session they used weights that were 80 percent of the weight at which they could just manage 1 rep [1RM].
Immediately after the session [IP], and 15 and 30 minutes later, the researchers observed that the concentration of testosterone and growth hormone in the men’s blood was higher than the previous measurement. But the increase in the two muscle-building hormones was considerably higher after the squat training than after the leg-press training session.
The men found both kinds of training session equally tiring.
When the researchers calculated the amount of effort the men had expended during the two sessions, they discovered why the concentrations of growth hormone and testosterone were higher after the squat session. Although the men used more weight on the leg-press machine their exertion was 42 percent higher during the squat session.
That’s because the men also had to work against their own bodyweight during the squats, and because the range of movement is greater during a squat than when using the leg press.
“At similar intensities and ratings of perceived exertion, the free weight (squat) exercise produces a greater acute hormonal response than the machine weight (leg press) exercise”, the researchers summarise. “The strength and conditioning professional should therefore consider choosing free weight exercises over machine weight analogs to induce a greater acute hormonal response, as this might subsequently result in superior physiological adaptations.”
The acute hormonal response to free weight and machine weight resistance exercise.
Shaner AA, Vingren JL, Hatfield DL, Budnar RG Jr, Duplanty AA, Hill DW.
Resistance exercise can acutely increase concentrations of circulating neuroendocrine factors, but the effect of mode on this response is not established. The purpose of this study was to examine the effect of resistance exercise selection on the acute hormonal response using similar lower-body multi-joint movement free weight and machine weight exercises. Ten resistance trained men (25±3 yr, 179±7 cm, 84.2±10.5 kg) completed 6 sets of 10 repetitions of squat or leg press at the same relative intensity separated by one week. Blood samples were collected before (PRE), immediately after (IP), and 15 (P15) and 30 min (P30) after exercise and analyzed for testosterone (T), growth hormone (GH), and cortisol (C) concentrations. Exercise increased (p<0.05) T and GH at IP but the concentrations at IP were greater for the squat (T: 31.4±10.3 nmol•L; GH: 9.5±7.3 ?g•L) than for the leg press (T: 26.9±7.8 nmol•L; GH: 2.8±3.2 ?g•L). At P15 and P30, GH was greater for the squat (P15: 12.3±8.9 ?g•L; P30: 12.0±8.9 ?g•L) than for the leg press (P15: 4.8±3.4 ?g•L; P30: 5.4±4.1 ?g•L). C was increased after exercise and was greater for the squat than for the leg press. Although total work (external load and body mass moved) was greater for the squat than for the leg press, rating of perceived exertion did not differ between modes. Free weight exercises appear to induce greater hormonal responses to resistance exercise than machine weight exercises utilizing similar lower-body multi-joint movements and primary movers.
PMID: 24276305 [PubMed – as supplied by publisher]