Mid Sweden University

Introduction

Interval cycle sprint training (SIT) has been shown to improve anaerobic capacity, VO₂max and biomarkers of muscle oxidative capacity in as little as 2 weeks in previously untrained adults. The present study was designed to characterize and compare systemic VO₂ and exercise performance after SIT engaging the arms and legs.

Methods

Sixteen healthy, untrained men (23.9 ± 3.7 yrs; 183.8 ± 6.8 cm; 80.3 ± 14.1 kg) performed six sessions of 4-6x30 sec all-out sprints with the legs then arms (or vice versa) separated by a 1-h recovery over an 11-day period. Limb-specific VO₂peak, anaerobic capacity (2x30-sec Wingate tests with 4 min of recovery), a 4-min submaximal work economy test, and a 5-min all-out time trial (TT) were conducted before and after the training program. Muscle biopsies (from the m. vastus lateralis and m. triceps brachii) were taken before and after the training period.

Results

VO₂peak increased by 10.6% and 5.9% with arm and leg training, respectively (p<0.05), with the increase in the arms significantly greater than in the legs (p=0.02). Work economy was improved for the arms (-9.8%, p<0.05), but not for the legs (-0.9%). Mean power during the TT rose by 13.5% for the arms and 11.8% for the legs (p<0.05). Peak power output and mean power during the two Wingate tests were elevated in both the arms (PPO: 6.7% (p<0.01) and 13.3% (p<0.01); MPO: 6.1% (p<0.01) and 8.4% (p<0.01)) and legs (PPO: 3.1% (p=0.07) and 7.1% (p=0.02); MPO: 3.3% (p<0.01) and 5.6% (p<0.01)). The activity of 3-hydroxyacyl-CoA dehydrogenase (HAD) and levels of muscle glycogen were unchanged in both limbs.

Discussion

Sprint interval training with arm or leg cycling exercise increased peak pulmonary VO₂ during their respective modes over an 11-day training period with a greater increase in the arms. Sprint performance rose to a similar extent in both extremities, yet work economy was improved only in the arms. These findings suggest some limb-specific responsiveness to SIT training.