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Maximal exercise has been performed by eight men and eight women, using four types of ergometer (2-leg, 1-leg, arm + shoulder, and arm) while breathing room air and while breathing 12% O2. Results have been related to anthropometric estimates of muscle mass in the active limbs. Although significant sex differences of O2 transfer and power output are shown, the sex-specific aerobic performance was roughly proportional to active muscle volume (both when comparing individuals on a given type of ergometer and when comparing average scores of the several types of ergometer). However, the relationship was closer for steady power output than for peak O2 intake (where the scores for arm work were boosted by the use of accessory muscles and by hyperventilation). When breathing 12% O2, the 2-leg performance was substantially reduced (an average of 28.7% for O2 transport and 19.2% for power output). This effect dropped to 9.1% for O2 transport and 12% for power output in one-leg ergometry and was negligible for arm or arm plus shoulder work. It is argued that because of difficulty in perfusing small muscles, arm work is limited largely by the intrinsic power of the active muscles, that single-leg ergometry is limited rather equally by central circulatory and muscular factors, and that two-leg ergometry is almost entirely dependent on the central circulatory transport of O2.

Performance over very short distances (1-5 m) is important in soccer. We investigated this in 23 male regional-level soccer players aged 17.2 +/- 0.7 years, filming body markers to determine the average velocity and acceleration over the first step (V(S) and A(S)) and the first 5 m (V(5), A(5)). Data were related to scores on a force-velocity test, squat jump (SJ), countermovement jump (CMJ), and 1 maximal repetition (1 RM) half back squat. Leg and thigh muscle volumes were also assessed anthropometrically. V(5) was positively correlated with leg and thigh muscle volumes (r = 0.61, p < 0.05; r = 0.43, p < 0.05, respectively), SJ power (absolute and relative to body mass, r = 0.45, p < 0.05; r = 0.43, p < 0.05, respectively), absolute force-velocity leg power (r = 0.49, p < 0.05), and 1 RM half back squat (r = 0.66, p < 0.001). The use of dimensional exponents did not change coefficients materially. V(S) was also correlated with leg muscle volume and 1 RM back half squat (r = 0.56, p < 0.01; r = 0.58, p < 0.01, respectively) and more weakly with force-velocity leg power and SJ force (r = 0.49, p < 0.05; r = 0.46, p < 0.5, respectively). However, the CMJ was unrelated to velocity or acceleration. Sprinting ability is correlated with measures of power and force such as the force-velocity test, SJ, and 1 RM half back squat; such measures thus offer useful guidance to soccer coaches who wish to improve the short-distance velocity of their players.

Ouergui, I, Houcine, N, Marzouki, H, Davis, P, Franchini, E, Gmada, N, and Bouhlel, E. Physiological responses and time-motion analysis of small combat games in kickboxing: impact of ring size and number of within-round sparring partners. J Strength Cond Res 31(7): 1840-1846, 2017-The study aimed to investigate the physiological responses and time-structure of small combat games (SCGs) in kickboxing according to ring sizes and number of sparring partners. Twenty athletes from regional (n = 13) and national levels (n = 7) participated in the study (mean ± SD, age: 20.3 ± 0.9 years; height: 177 ± 4.8 cm; body mass: 71.8 ± 10.5 kg). Blood lactate concentration [La] was measured before and after bouts, and the delta (Δ) was determined. Heart rate (HR) was measured throughout and HR and rating of perceived exertion (RPE) were also measured postbout. The HRpre, HRmean, and percentage of peak HR (%HRpeak) were used for analysis. The HRpeak was determined during a cycle ergometer graded exercise test. Each athlete was confronted by 1 (1 vs. 1; no sparring partner change), 2 (1 vs. 2) and 4 opponents (1 vs. 4) within-round (sparring partner change every 1 minute or 30 seconds, respectively) in different ring sizes (i.e., 2×2 m, 4×4 m, and 6×6 m). All combats were recorded and analyzed to determine the duration of different activity phases (high-intensity activities [HIA], low-intensity actions [LIA], and referee pause [P]). Results showed that values for HRpre and HRmean when opposed by a single individual (1 vs. 1) were lower than other conditions (all p< 0.001). Moreover, %HRpeak values in 1 vs. 1 were lower than in other conditions and higher in 4 × 4 m compared with other sizes. [La]pre, post, and the Δ did not differ among all conditions (p > 0.05). The RPE scores were lower in 1 vs. 1 compared with other conditions (p < 0.001), with no ring sizes effect (p > 0.05). For time-motion variables, HIA values were lower in 1 vs. 1 than in the 2 other conditions and was longer in 2 × 2 m compared with 4 × 4 m and 6 × 6 m, whereas LIA values were higher in 1 vs. 1 and lower in the 2 × 2 m. In conclusion, SCGs seem to be a good form of exercise for sufficient cardiovascular conditioning specific to kickboxing activity in comparison with data from previous studies.