Repeated Sprint Training in Heat Improves Repeated Sprint Ability Under Temperate Conditions Similarly in Active Males and Females.

Repeated sprint training in heat (RSHT) significantly increased sprint number during the repeated sprint ability (RSA) test in both males and females, without significant changes in the control group.

• Sprint number during RSA increased after HEAT from 15 to 21 in males and from 8 to 13 in females (p < 0.001).
• No significant changes in sprint number were observed after CON (temperate training) in either sex.
• Training was conducted twice a week for 7 weeks in either temperate (20°C, 55% RH) or hot (30°C, 60% RH) conditions.
• The RSA test consisted of 10-s cycle sprints with 20-s recovery between sprints, performed until exhaustion.

The improvement in repeated sprint ability with RSHT was similar between males and females.

• Males increased sprint number from 15 to 21 and females from 8 to 13 in the HEAT condition.
• The study concluded that RSHT increased the number of repeated sprints performed under temperate conditions in females to the same extent as in males.
• Male HEAT group: n = 12; female HEAT group: n = 14.
• Male CON group: n = 12; female CON group: n = 13.

VO2peak increased across all groups following the training intervention regardless of condition or sex.

• VO2peak during an incremental exercise test increased by +3 ± 1 mL·kg-1·min-1 (p = 0.032) in all groups.
• This improvement was not specific to the heat training condition, as it occurred in both HEAT and CON groups.
• Aerobic qualities were evaluated in temperate conditions before and after training.

Mean power output during a Wingate test increased across all groups following training.

• Mean power output during a Wingate test increased by +0.41 ± 0.15 W·kg-1 (p = 0.007) in all groups.
• This improvement occurred regardless of training condition (heat or temperate) and sex.
• Anaerobic qualities were evaluated in temperate conditions before and after training.

RSHT induced partial heat acclimation as evidenced by reductions in core temperature and thermal sensation during training, but without changes in sweat rate or sweat sodium concentration.

• In the HEAT group only, the change in core temperature was lower at TR12 than TR1 by -0.16 ± 0.07°C (p = 0.015).
• Thermal sensation was lower at TR12 than TR1 by -1 ± 0 (p < 0.001) in the HEAT group only.
• No changes were observed in skin temperature between TR1 and TR12.
• No changes were observed in sweat rate or whole-body sweat sodium concentration, indicating incomplete heat acclimation.
• Thermoregulatory responses were measured on Training 1 (TR1) and Training 12 (TR12).

No changes in hematological parameters were observed following either training condition.

• Hematological parameters remained unchanged across both HEAT and CON groups and in both sexes.
• This suggests plasma volume expansion was not a mechanism underlying the observed performance improvements with RSHT.