Inspiratory and Lower-Limb Strength Importance in Mountain Ultramarathon Running. Sex Differences and Relationship with Performance

Abstract

The study was aimed at comparing lower-limb strength and respiratory parameters between male and female athletes and their interaction with performance in a 107 km mountain ultramarathon. Forty seven runners (29 males and 18 females; mean ± SD age: 41 ± 5 years) were enrolled. Lower-limb strength assessment comprised a squat jump test, an ankle rebound test, and an isometric strength test. Respiratory assessment included pulmonary function testing and the measurement of maximal inspiratory pressure. Male athletes performed largely better in the squat jump (26 ± 4 vs. 21 ± 3 cm; p < 0.001; d = 1.48), while no sex differences were found in the other two lower-limb tests. Concerning the respiratory parameters, male athletes showed largely greater values in pulmonary expiratory variables: forced vital capacity (5.19 ± 0.68 vs. 3.65 ± 0.52 L; p < 0.001; d = 2.53), forced expiratory volume in 1 s (4.24 ± 0.54 vs. 2.97 ± 0.39 L; p < 0.001; d = 2.69), peak expiratory flow (9.9 ± 1.56 vs. 5.89 ± 1.39 L/min; p < 0.001; d = 2.77) and maximum voluntary ventilation in 12 s (171 ± 39 vs. 108 ± 23 L/min; p < 0.001; d = 1.93); while no sex differences were identified in maximal inspiratory pressure. Race time was associated with ankle rebound test performance (r = −0.390; p = 0.027), isometric strength test performance (r = −0.349; p = 0.049) and maximal inspiratory pressure (r = −0.544; p < 0.001). Consequently, it seems that athletes competing in mountain ultramarathons may benefit from improving lower-limb isometric strength, ankle reactive strength and inspiratory muscle strength. Nevertheless, further interventional studies are required to confirm these exploratory results. In addition, the fact that the magnitude of the sex difference for isometric strength was minor, as compared with the other strength tests, could represent one of the factors explaining why the performance gap between males and females is reduced in ultramarathons.

Training, Anthropometric, and Physiological Characteristics in Men Recreational Marathon Runners: The Role of Sport Experience

“…Accordingly, the negative correlation of the number of finished marathons with SJ and CMJ might reflect a training adaptation to endurance training. This finding was in agreement with previous research (Martinez-Navarro et al, 2020) that observed a trend that fast runners exhibited relatively low SJ, too. With regard to the variation of skinfold thickness and body fat between the two groups, EXP had smaller thickness in two skinfolds (abdominal and iliac crest) and lower BF estimated by BIA than NOV.…”

Is There Evidence for the Development of Sex-Specific Guidelines for Ultramarathon Coaches and Athletes? A Systematic Review

“…Five of the six studies found sex differences in the predictors of performance. Martinez-Navarro et al found that mean inspiratory pressure was correlated with performance in males only ( r = − 0.576, p = 0.010) [ 28 ]. In females, the Leg Qindex was the only variable that correlated with performance ( r = − 0.607, p = 0.028) [ 28 ].…”

“…Martinez-Navarro et al found that mean inspiratory pressure was correlated with performance in males only ( r = − 0.576, p = 0.010) [ 28 ]. In females, the Leg Qindex was the only variable that correlated with performance ( r = − 0.607, p = 0.028) [ 28 ]. In another paper, Martinez-Navarro et al reported that Vpeak, or the top speed measured during treadmill cardiopulmonary exercise testing (CPET), and maximal fat oxidation rate (MFO) together explained 66% of the variation in 107 km race time in males [ 16 ].…”

“…This is important as it could translate into different training priorities for each sex. For example, a strong correlation between ankle rebound performance and female ultramarathon performance was demonstrated by Martinez-Navarro et al [ 28 ] Conversely, mean inspiratory pressure was correlated to performance in males only [ 28 ]. Indeed, there is evidence that females have superior fatigue resistance of the respiratory muscles, indicating that this may be less of a performance limiting factor than in males [ 69 ].…”

“…Six studies investigated sex differences in the physiological predictors of ultramarathon performance in 228 subjects, 80 of whom were female (Table 1) [15,16,[26][27][28][29]. These studies looked at a wide range of parameters, including limb strength, cardiopulmonary function, body composition, and substrate utilisation.…”