Supplementing conventional boxing training with HIIT may serve as a useful strategy for enhancing selected pulmonary function parameters in combat sports athletes, though improvements cannot be definitively attributed to HIIT independently of increased training volume.
Key Findings
Results
Significant improvements in multiple pulmonary function measures were observed over time following a 4-week HIIT-boxing regimen.
Maximal voluntary ventilation, forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), and peak expiratory flow all improved significantly over time (P < .01)
The FEV1/FVC ratio remained unchanged across the intervention period (P = .244)
16 trained young individuals were randomly assigned to either the HIIT-boxing group or a control group
Assessments were conducted pre- and post-intervention using comprehensive pulmonary function tests
Results
Time-by-group interactions revealed greater pulmonary function improvements in the HIIT-boxing group compared to the control group for several key measures.
Maximal voluntary ventilation showed the largest differential improvement with a large effect size (ηp2 = 0.817)
FVC showed a large differential improvement in the HIIT group (ηp2 = 0.618)
FEV1 showed a moderate differential improvement in the HIIT group (ηp2 = 0.283)
These effect sizes indicate that the HIIT group outperformed the control group on these specific pulmonary measures
Results
Estimated maximal oxygen uptake improved significantly over time but without a significant group effect or time-by-group interaction.
Estimated VO2max improved significantly over time across both groups (P < .001)
No significant group effect was observed for estimated VO2max
No significant time-by-group interaction was observed for estimated VO2max
This suggests both HIIT-boxing and control groups experienced similar aerobic capacity changes
Results
Heart rate recovery improved significantly over time in both groups, with no significant difference between the HIIT-boxing and control groups.
HRR improved significantly over time in both groups (P < .001)
HRR was measured at the 1st, 3rd, and 5th minutes post-exercise as an indicator of autonomic cardiovascular regulation
No significant time-by-group interaction was observed at any measured interval (P > .05)
This suggests conventional boxing training alone was sufficient to improve autonomic cardiovascular regulation similarly to HIIT-supplemented training
Discussion
The observed pulmonary function improvements in the HIIT group cannot be definitively attributed to HIIT independently of increased total training volume.
The HIIT group performed a greater total training volume than the control group during the 4-week intervention
Authors acknowledge this as a key limitation in attributing the improvements specifically to the HIIT stimulus
The study design did not fully isolate HIIT as the independent variable from total training load
A 4-week intervention period was used, which is relatively short for assessing long-term physiological adaptations
Methods
The study used a randomized controlled design with 16 trained young individuals over a 4-week structured HIIT-boxing intervention.
Participants were randomly assigned to either the HIIT-boxing group or the control group
Total sample size was 16 trained young individuals
The intervention lasted 4 weeks
Outcome measures included pulmonary function tests, peak oxygen uptake (estimated VO2max), and heart rate recovery at 1, 3, and 5 minutes post-exercise
What This Means
This research suggests that adding high-intensity interval training (HIIT) to a standard boxing training program can lead to meaningful improvements in lung function — specifically in how much air athletes can move in and out of their lungs forcefully and quickly. Over just four weeks, young boxers who supplemented their training with HIIT showed notably greater gains in measures like forced vital capacity, forced expiratory volume, and maximal voluntary ventilation compared to those who only did conventional boxing training. However, the ability to generate oxygen efficiently (aerobic capacity) and the heart's ability to recover quickly after exercise both improved in both groups equally, suggesting that regular boxing training alone may be sufficient for those particular fitness qualities.
One important caveat highlighted by the researchers is that the HIIT group trained more in total volume than the control group, making it difficult to say with certainty whether the lung function improvements were due to the specific nature of HIIT or simply because those athletes did more overall training. This distinction matters because it affects whether coaches and athletes should specifically seek out HIIT or just increase their training load in general.
This research suggests that for combat sports athletes like boxers, incorporating HIIT into their training routine could be a practical strategy to boost respiratory fitness, which may benefit their performance in the ring. However, future studies with larger groups, longer durations, and better-matched training volumes between groups will be needed to confirm whether HIIT itself — rather than simply more training — is responsible for these benefits.
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Cinarli S, Akyol B, Karakurt F, Mutlu K, Tutar M, Cinarli F, et al.. (2026). Cardiorespiratory adaptations to high-intensity interval training in young boxers: A randomized controlled study.. Medicine. https://doi.org/10.1097/MD.0000000000050694