Author(s): REALE, R., WANG, J., RITCHIE, D., FRENCH, D., HU-STULL, C., AMASINGER, D., WANG, R., Institution: UFC PERFORMANCE INSTITUTE, Country: CHINA, Abstract-ID: 1404

INTRODUCTION:
Large data sets exist for typical sweat rates, fluid intakes, and daily hydration status of athletes across a wide variety of sports. Despite this, few data in combat sports, and none in mixed martial arts (MMA) are available. With the importance of hydration status in both performance and health contexts, combined with the intentional dehydration practices combat athletes use to facilitate acute weight loss to ‘make weight’, detailed investigations are warranted.
METHODS:
Thirteen professional male MMA athletes took part in a study across a normal training week (Monday to Saturday, including different technical and non-technical sessions), which assessed waking hydration status (measured via urine specific gravity (USG)) alongside training sweat losses, fluid intake, and net body mass (BM) changes. Additionally, we compared training sweat losses to a typical hot water immersion (HWI) protocol (20 min at 41 C, followed by 20 min wrapped in towels) used to induce sweat losses, to understand differences in active vs passive dehydration modalities (both commonly used to make weight). Comparison of daily USG, fluid balance variables between training sessions, and HWI vs sweat losses, were analyzed using one-way repeated measures ANOVAs.
RESULTS:
Average hourly sweat losses, fluid intake, and BM changes were 1.30 ± 0.38 BM%, 898 ± 244 mL, and +0.12 ± 0.28 BM%, respectively. Significant differences with large effect sizes (d>0.8) in sweat rate and fluid intake between some sessions were found (p<0.0125), however no differences in BM changes were found between sessions. Average USG was 1.025 ± 0.004, with a significant linear trend found for USG to increase across the week (p=0.025). Differences between active and passive sweating were significant (p <0.00001). When comparing HWI to athlete’s minimum, mean, and maximum sweat rates, HWI resulted in 4.09 ± 1.52 x, 2.26 ± 0.39 x, and 1.61 ± 0.26 x the BM losses, respectively.
CONCLUSION:
MMA training results in sweat losses similar to average values reported in other sports. Training session type seems to affect sweat rates, however, athletes increase fluid intake in response, resulting in similar BM changes across all session types. When athletes have adequate fluid access, they are at little risk of meaningful dehydration during training. Fluid intake may be suboptimal outside of training times based on waking USG, and this may compound across a training week. However, it is not understood if confounding dietary or physical activity factors impact USG readings (e.g. proteinuria, haematuria, elevated creatinine). Finally, passive dehydration methods appear a more effective method of acute weight loss, based on the greater hourly sweat rate, and the absence of muscular fatigue induced. The caveat is that significant passive dehydration should only be implemented when athletes are provided the time to adequately recover post weigh-in, and athletes, coaches, and support staff are mindful of the heat stress associated with such techniques.