Impact of sprint interval training on post fatigue mitochondrial rate in professional boxers

Purpose: Professional boxing is a sport that requires a high aerobic capacity to prevent fatigue and allow athletes to perform over 4–12 rounds. Typically, athletes will go into a heavy training period in a pre-bout camp lasting 6 to 9 weeks. This study investigates the impact of 3 weeks of repeated Wingate sprint interval training, performed on standard gym ergometer bikes, on skeletal muscle endurance and mitochondrial function. 

Methods: Ten male professional boxers (age: 26 ± 4 years, height: 175 ± 5 cm, weight: 70 ± 5 kg) participated in the study. Baseline testing involved a NIRS monitor attached to the rectus femoris muscle prior to an incremental time to exhaustion test on a treadmill. After the treadmill test participants underwent a series of arterial occlusions to determine mitochondrial function post-volitional exhaustion. Participants then continued their own training for 3 weeks and then repeated baseline testing. After the second testing session, participants undertook three weekly sprint sessions consisting of 3 × 30 s maximal sprints with 60 s recovery. Testing was repeated 3 weeks later. 

Results: The time to exhaustion increased by > 6% after 3 weeks of sprint interval training as compared to baseline and control (p < 0.05). Skeletal muscle oxygen saturation (SmO₂) at exhaustion was increased by 5.5% after 3 weeks of sprint interval training as compared to baseline and control (p = 0.008). Skeletal muscle mitochondrial rate post exhaustion was increased by 160% after 3 weeks of sprint interval training as compared to baseline and control (p < 0.001). 

Conclusion: The study demonstrated that SIT led to increased incremental time to exhaustion, higher SmO₂ levels at volitional exhaustion and increased mitochondrial rates in professional boxers. These findings suggest that SIT should be an integral part of a boxe’s conditioning regimen to improve performance and safety within the ring.