|HIIT - A GH diminishing mass builder?|
In their latest paper which appeared in the December edition of the Journal of Exercise Physiology Kevin Ritsche, Jason Smith, Paul Mellick, and Laurie Wideman report the results of a recent experiment in the course of which 19 recreationally active male subjects (24.9 ± 3.9 yrs) completed a one-week high intensity interval training.
The training protocol used in the study was based on similar high-intensity protocols published by Burgomaster et al. (2005) and Gibala et al. (2006) and began 24 hrs after the completion of a pre-test that was designed to measure the baseline fitness, body fat and lean body mass (by DEXA), as well as the acute GH response to high intensity exercise in the 19 young subjects.
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 (wk 2) consisted of 5 repetitions, and sessions 7 to 9 (wk 3) consisted of six 30-sec maximal repetitions. During each repetition, each subject was encouraged verbally to provide maximal effort" (Ritsche. 2014).At the end of each week, 48 hrs after the third training session for the week, subjects completed the acute sprint test protocol outlined previously (including blood draws).
- Burgomaster, Kirsten A., et al. "Six sessions of sprint interval training increases muscle oxidative potential and cycle endurance capacity in humans." Journal of applied physiology 98.6 (2005): 1985-1990.
- Gibala, Martin J., et al. "Short-term sprint interval versus traditional endurance training: similar initial adaptations in human skeletal muscle and exercise performance." The Journal of physiology 575.3 (2006): 901-911.
- 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).