Shock Your Legs into New Growth
If you ask any athletes how to get bigger legs, most will tell you that you have to squat. How would you like to add 2 lbs. of lean muscle mass to your legs without squatting in three weeks. That’s exactly what researchers reported in the latest Journal of Exercise Physiology in which 19 recreationally active male subjects completed a three-week high intensity interval training on a cycle ergometer. The other interesting finding of the study was that the leg muscle growth occurred in the absence of acute increases in GH production.
Researchers wanted to examine the time course and magnitude of the GH adaptation, anthropometric and anaerobic performance changes to 3 weeks of high-intensity sprint exercise training on a cycle ergometer using a weekly measure of hormonal responses and exercise performance. The training protocol consisted of 4 to 6 repetitions of 30-sec maximal sprints and was performed three times per week for 3 weeks. One day of rest intervened each training session. The first 3 training sessions consisted of four 30-sec repetitions at 7.5% body mass with 4 min of active recovery at 50 W between each repetition. Training sessions 4 to 6 (weeks 2) consisted of 5 repetitions, and sessions 7 to 9 (week 3) consisted of six 30-sec maximal repetitions. During each repetition, each subject was encouraged verbally to provide maximal effort.
At the end of three weeks of HIIT training, the major findings of this study indicated significant increases in total and leg lean mass, albeit only non-significant reductions in body fat – changes which went hand in hand with a profound increase in exercise performance. Its interesting that just by doing HIIT training on a cycle to all out failure led to some significant increases in leg growth without ever getting under a squat bar. The other interesting finding was that there was leg growth despite attenuated reductions in GH responses that occurred with the sprint training. This attenuation in GH release occurred after sequentially increasing workload each week of training; and in concert with the increase in lean mass of the lower extremities and greater peak power anaerobic performance.
Key Points of the Study:
- The training protocol consisted of 4 to 6 repetitions of 30-sec maximal sprints and was performed three times per week for 3 weeks. One day of rest intervened each training session.
- One day of rest intervened each training session.
- At the end of three weeks of HIIT training, the major findings of this study indicated significant increases in total and leg lean mass.
Ritsche, Kevin, et al. “Acute Exercise-Induced Growth Hormone is Attenuated in Response to Short-Term, High-Intensity Exercise Training.” Journal of Exercise Physiology (2014).