There are no studies in the literature to validate equations that predict maximum heart rate (HRmax) in children and adolescents. To analyze the validity of the HRmax predictive equations "220 - age" and "208 - (0.7 x age)" in boys aged 10 and 16. A progressive maximal exertion test was carried out in 69 apparently healthy boys aged 10 to 16. The initial test velocity was 9 km/h, with 1-km/h increments every three minutes. The test was maintained until maximum voluntary exertion was achieved, considering HRmax as the highest heart rate attained during the test. The measured HRmax was compared with the values predicted by the "220 - age" and "208 - (0.7 x age)" equations, using ANOVA for repeated measures. The mean values of HRmax (bpm) were: 200.2 ± 8.0 (measured), 207.4 ± 1.5 ("220 - age") and 199.2 ± 1.1 ("208 - (0.7 x age)"). The HRmax predicted by the "220 - age" equation was significantly higher (p < 0.001) than the measured HRmax and the HRmax predicted by the ("208 - (0.7 x age)") equation. The correlation between the measured HRmax and age was not statistically significant (r = 0.096; p > 0.05). The "220 - age" equation overestimated the measured HRmax and was not valid for this population. The "208 - (0.7 x age)" equation was valid for this population, showing results that were quite similar to those of measured HRmax. Future studies with larger sample sizes can verify whether the HRmax does not depend on age for this population, a situation in which the constant 200 bpm value would be more appropriate for HRmax.

To determine the effects of preparatory phase training on aerobic parameters, resting heart rate variability (HRV) and 5-km performance of high-level endurance runners and the relationship between the percentage change (% change) of resting HRV with the % change of aerobic parameters and 5-km performance. Six runners were assessed before and after seven weeks of training. The aerobic parameters were determined in an incremental test. The HRV was assessed by a heart rate monitor. Athletes performed a 5-km running test in a track. The analysis revealed likely' and very likely' improvements for velocity associated with maximal oxygen uptake (VO2max) (20.0 +/- 1.0 km center dot h(-1) to 21.2 +/- 0.6 km center dot h(-1)) and 5-km performance (18.0 +/- 0.4 km center dot h(-1) to 18.9 +/- 0.7 km center dot h(-1)), respectively, as well as likely' decrease in high frequency (41.4 +/- 18.5 nu to 30.4 +/- 14.3 nu), and increase in low frequency (58.5 +/- 18.5 nu to 69.6 +/- 14.3 nu) band densities. The variation in the velocity associated with VO2max showed the highest correlation with 5-km performance (r=0.95). The % change in the square root of the mean sum of the squared differences between R-R intervals and standard deviation 1 were highly correlated with variation in 5-km performance (r=0.69 and 0.66). Changes in the velocity associated with VO2max and vagally mediated HRV were highly associated with 5-km running performance within the investigated team. These results have important implications because these parameters can be assessed longitudinally to monitor adaptation to training.

This study aimed to investigate the influence of endurance running training associated with PBM on endurance performance variables and muscle soreness in untrained men. Thirty untrained men were distributed randomly into a placebo (PLA) group and photobiomodulation group (PBMG) and they performed 8 weeks of running training. The PBMG had the PBM performed before all training sessions. The PBM was applied using LED equipment with 56 diodes of red light (660 nm) and 48 diodes of infrared light (850 nm). The application was performed in 5 points per leg, with a dose of 60 J at each point and a total energy delivered per leg of 300 J. Peak running velocity, time limit tests and 5-km performance were assessed pre and post-training; muscle soreness was evaluated before all training sessions. The V_peak increased and 5-km running time (t_5–km) decreased (P < 0.001) in both groups. In addition, the magnitude based-inference analysis showed a possibly positive effect on V_peak and t_5–km and for PBMG compared to PLA group. Furthermore, there was a moderate ES of 0.82 on attenuation in muscle soreness in the third week of endurance running training. Therefore, although the magnitude-based inference analysis demonstrated a possibly positive effect on V_peak and t_5–km and for PBMG compared to PLA group and a moderate ES on attenuation in muscle soreness in the last weeks of endurance running training, no significant difference were found between PBMG and PLA interventions.

This study compared the effects of 4 weeks of training prescribed by peak velocity (V_peak) or velocity associated with maximum oxygen uptake (vVO_2max) in moderately trained endurance runners. Study participants were 14 runners (18–35 years) randomized into 2 groups, named group VO₂ (GVO₂) and group V_peak (GVP). The GVO₂ had training prescribed by vVO_2max and its time limit (t_lim), whereas the GVP had training prescribed by V_peak and its t_lim. Four tests were performed on a treadmill: 2 maximum incremental for V_peak and vVO_2max and 2 for their t_lim. Performance (10 km) was evaluated on a 400 m track. Evaluations were repeated after 4 weeks of endurance training. The results showed a significant effect of training on V_peak [GVP (16.7±1.2–17.6±1.5 km^.h⁻¹), GVO₂ (17.1±1.9–17.7±1.6 km·h⁻¹)]; vVO_2max [GVP (16.4±1.4–17.0±1.3 km·h⁻¹), GVO₂ (17.2±1.7–17.5±1.9 km·h⁻¹)]; and 10 km performance [GVP (41.3±2.4–39.9±2.7 min), GVO₂ (40.1±3.4–39.2±2.9 min)]. The V_peak highly correlated with performance in both pre- and post-training in GVP (–0.97;–0.86) and GVO₂ (–0.95;–0.94), as well as with vVO_2max in GVP (–0.82;–0.88) and GVO₂ (–0.99; –0.98). It is concluded that training prescribed by V_peak promoted similar improvements compared to training prescribed by vVO_2max. The use of V_peak is recommended due to its practical application and the low cost of determination.