Aerobic high‐intensity intervals improve V̇O2max more than supramaximal sprint intervals in females, similar to males

• Published in: Scandinavian journal of medicine & science in sports Vol. 33; no. 11; pp. 2193 - 2207
• Main Authors: Helgerud, Jan, Hov, Håkon, Mehus, Håkon, Balto, Bård, Boye, Anders, Finsås, Lars, Hoff, Jan, Wang, Eivind
• Format: Journal Article
• Language: English
• Published: Oxford Blackwell Publishing Ltd 01.11.2023
• Subjects: Injuries; Interval training; Males
• ISSN: 0905-7188; 1600-0838
• DOI: 10.1111/sms.14470

IntroductionMaximal oxygen uptake (V̇O2max) is a pivotal factor for aerobic endurance performance. Recently, aerobic high‐intensity interval training (HIIT) was documented to be superior to sprint interval training (SIT) in improving V̇O2max in well‐trained males. However, as mounting evidence suggests that physiological responses to training are sex‐dependent, examining the effects of HIIT versus SIT on V̇O2max, anaerobic capacity, and endurance performance in females is warranted.MethodsWe randomized 81 aerobically well‐trained females (22 ± 2 years, 51.8 ± 3.6 mL∙kg−1∙min−1 V̇O2max), training three times weekly for 8 weeks, to well‐established protocols: (1) HIIT 4 × 4 min at ~95% of maximal aerobic speed (MAS), with 3 min active recovery (2) SIT 8 × 20 s at ~150% of MAS, with 10 s passive recovery (3) SIT 10 × 30 s at ~175% of MAS, with 3.5 min active recovery.ResultsOnly HIIT 4 × 4 min increased V̇O2max (7.3 ± 3.1%), different from both SIT groups (all p < 0.001). Anaerobic capacity (maximal accumulated oxygen deficit) increased following SIT 8 × 20 s (6.5 ± 10.5%, p < 0.05), SIT 10 × 30 s (14.4 ± 13.7%, p < 0.05; different from HIIT 4 × 4 min, p < 0.05). SIT 10 × 30 s resulted in eight training‐induced injuries, different from no injuries following HIIT 4 × 4 min and SIT 8 × 20 s (p < 0.001). All groups improved long‐distance (3000‐meter) and sprint (300‐meter) running performance (all p < 0.001). SIT protocols improved sprint performance more than HIIT 4 × 4 min (p < 0.05). Compared to previous male results, no increase in V̇O2max following SIT 8 × 20 s (p < 0.01), and a higher injury rate for SIT 10 × 30 s (p < 0.001), were evident.ConclusionsIn aerobically well‐trained women, HIIT is superior to SIT in increasing V̇O2max while all‐out treadmill running SIT is potentially more harmful.