The use of saliva to monitor immune and hormonal responses in training, competitions, and during recovery is an easy and non-invasive alternative means of collecting samples compared to serum collection. Saliva can provide insight into a number of interesting biomarkers such as cortisol, testosterone, immunoglobulins, alpha-amylase, and melatonin, among others. High-intensity and exhaustive exercises, such as training or competition, provide variations in immune, protein and hormonal markers. An adequate recovery period, calming down, and recovery methods can contribute to a fast normalization of these markers, decreasing illness, as well as the likelihood of overtraining and injuries, but their effectiveness is still inconclusive. The aim of this review was to investigate the evidence of salivary markers in post-exhaustive exercise during the recovery period. This study is a systematic review from three electronic databases with studies from 2011 to 2021 within healthy humans. The search found 213 studies, and after applying the inclusion and exclusion criteria, while excluding duplicated studies, 14 studies were included in this review. The most cited salivary markers were cortisol and testosterone, as well as their ratio, alpha-amylase and IgA. Half of the studies applied a variety of recovery methods that showed controversial results over salivary markers’ impact. However, they showed an impact on the markers from the exercise, which was still dependent on exercise intensity, methodology, and duration.

We purposed to study energy expenditure, power output and gross efficiency during kayak ergometer exercise in 12 elite sprint kayakers. 6 males (age 24.2±4.8 years, height 180.4±4.8 cm, body mass 79.7±8.5 kg) and 6 females (age 24.3±4.5 years, height 164.5±3.9 cm, body mass 65.4±3.5 kg), performed an incremental intermittent protocol on kayak ergometer with V˙O₂ and blood lactate concentration assessment, a non-linear increase between power output and energy expenditure being observed. Paddling power output, energy expenditure and gross efficiency corresponding to V˙O₂max averaged 199.92±50.41 W, 75.27±6.30 ml.kg^− 1.min^− 1, and 10.10±1.08%. Male kayakers presented higher V˙O₂max, power output and gross efficiency at the V˙O₂max, and lower heart rate and maximal lactate concentration than females, but no differences were found between genders regarding energy expenditure at V˙O₂max. Aerobic and anaerobic components of energy expenditure evidenced a significant contribution of anaerobic energy sources in sprint kayak performance. Results also suggested the dependence of the gross efficiency on the changes in the amount of the aerobic and anaerobic contributions, at heavy and severe intensities. The inter-individual variance of the relationship between energy expenditure and the corresponding paddling power output revealed a relevant tracking for females (FDγ=0.73±0.06), conversely to the male group (FDγ=0.27±0.08), supporting that some male kayakers are more skilled in some paddling intensities than others.

Age- and sex-related differences in optimal peak power (PP_opt) and associated measures determined using a force-velocity (F-V) cycling test were examined in pre teenage, teenage and adult males and females. Absolute PP_opt increased significantly with age in both males and females. With body mass controlled for using allometric scaling significant age related increases remained, an effect masked in the females when PP_opt was expressed as W • kg⁻¹. Sex differences in PP_opt were minimal in the preteens but males demonstrated higher PP_opt than females in both teenage and adult groups. These patterns of change with age and sex broadly reflect those obtained for Wingate Anaerobic Test determined PP but the use of a single non-optimized braking force underestimates the magnitude of any differences observed.

Peak oxygen uptake (V̇O_2peak) is routinely expressed in litres per minute and by unit of body mass (mL·kg⁻¹·min⁻¹) despite the theoretical and statistical limitations of using ratios. Allometric modeling is an effective approach for partitioning body-size effects in a performance variable. The current study examined the relationships among chronological age (CA), skeletal age (SA), total body and appendicular size descriptors, and V̇O_2peakin male adolescent roller hockey players. Seventy-three Portuguese, highly trained male athletes (CA, 15.4 ± 0.6 years; SA, 16.4 ± 1.5 years; stature, 169.9 ± 6.9 cm; body mass, 63.7 ± 10.7 kg; thigh volume, 4.8 ± 1.0 L) performed an incremental maximal test on a motorized treadmill. Exponents for body size descriptors were 2.15 for stature (R²= 0.30, p < 0.01) and 0.55 for thigh volume (R²= 0.46, p < 0.01). The combination of stature or thigh volume and CA or SA, and CA²or SA², increased the explained variance in V̇O_2peak(R²ranged from 0.30 to 0.55). The findings of the allometric model combining more than 1 body size descriptor (i.e., stature and thigh volume) in addition to SA and CA²were not significant. Results suggest that thigh volume and SA are the main contributors to interindividual variability in aerobic fitness.

In recent years, there has been an exponential increase in the number of devices developed to measure or estimate physical exercise. However, before these devices can be used in a practical and research environment, it is necessary to determine their validity and reliability. The purpose of this study is to test the validity and reliability of a load cell sensor-based device (LC) for measuring the peak force (PFr) and the rate of force development (RFD) during the isometric mid-thigh pull (IMTP) test, using a force plate (FP) as the gold standard. Forty-two undergraduate sport science students (male and female) participated in this study. In a single session, they performed three repetitions of the IMTP test, being tested simultaneously with an LC device and a Kistler force platform (FP). The PFr and RFD data were obtained from the force-time curve of the FP and compared with the LC data, provided automatically by the software of the device (Smart Traction device©). The mean difference between the results obtained by the LC device and the gold-standard equipment (FP) was not significantly different (p > 0.05), for both PFr and RFD, which suggests the validity of the ST results. Bland–Altman analysis showed a small mean difference in PFr = 1.69 N, upper bound = 47.88 N, and lower bound = −51.27 N. RFD showed that the mean difference was −5.27 N/s, upper limit = 44.36 N/s, and lower limit = −54.91 N/s. Our results suggest that the LC device can be used in the assessment of the isometric-mid-thigh-pull test as a valid and reliable tool. It is recommended that this device’s users consider these research results before putting the ST into clinical practice.