Effect of 6 weeks of sprint training on growth hormone responses to sprinting.
This study examined the effect of 6 weeks of prescribed sprint training on the human growth hormone (hGH) response to cycle ergometer sprinting. Sixteen male subjects were randomly assigned to a training (n=8) or a control (n=8) group. Each subject completed two main trials, consisting of two all-out 30-s cycle-ergometer sprints separated by 60 min of passive recovery, once before, and once after a 6-week training period. The training group completed three supervised sprint-training sessions per week in addition to their normal activity, whilst control subjects continued with their normal activity. In the training group, peak and mean power increased post-training by 6% (P<0.05) and 5% (P<0.05), respectively. Post-exercise blood pH did not change following training, but the highest post-exercise blood lactate concentrations were greater [highest measured value: 13.3 (1.0) vs 15.0 (1.1) mmol l(-1)], with lower blood lactate concentrations for the remainder of the recovery period (P<0.05). Post-exercise plasma ammonia concentrations were lower after training [mean highest measured value: 184.1 (9.8) vs 139.0 (11.7) micromol l(-1), P<0.05]. Resting serum hGH concentrations did not change following training, but the peak values measured post-exercise decreased by over 40% in the training group [10.3 (3.1) vs 5.8 (2.5) microg l(-1), P<0.05], and mean integrated serum hGH concentrations were 55% lower after training [567 (158) vs 256 (121) min microg l(-1), P<0.05]. The hGH response to the second sprint was attenuated similarly before and after training. This study showed that 6 weeks of combined speed- and speed-endurance training blunted the human growth hormone response to sprint exercise, despite an improvement in sprint performance.
Department of Sport and Exercise Science, University of Bath, BA2 7AY, Bath, UK. K.Stokes@bath.ac.uk
Keith A
KA
Stokes
Mary E
ME
Nevill
Paul W
PW
Cherry
Henryk K A
HK
Lakomy
George M
GM
Hall
D000222:Adaptation, Physiological / Q000502:physiology; D000328:Adult; D004734:Energy Metabolism / Q000502:physiology*; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test / Q000379:methods; D013006:Growth Hormone / Q000097:blood*; D006801:Humans; D019344:Lactic Acid / Q000097:blood*; D008297:Male; D010806:Physical Education and Training / Q000379:methods*; D010807:Physical Endurance / Q000502:physiology*; D005082:Physical Exertion / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology
D019344:Lactic Acid; D013006:Growth Hormone