The increase of wide-spread participation in endurance events in sports such as open water swimming, cycling, running and triathlons, has given rise to a concern about potential implications for renal function and kidney health. This study aimed to delve into the findings on exertional rhabdomyolysis (ER) and acute kidney injury (AKI) in endurance sports, emphasizing the diagnostic criteria used, physical and environmental contextual conditions in which ER and AKI are reported. Following PRISMA guidelines for systematic reviews and meta-analysis, topic related studies were searched digital sources (from 2009 to 2020). Studies with biomarkers of ER and AKI reported in endurance or ultra-endurance events were included. A total of 43 publications (sample = 813) were extracted, and 345 (43.5%) individuals were diagnosed with ER (creatinine kinase > 5000 UI/L) and 130 (16.39%) with ER + AKI (creatinine ≥ 1.88 mg/dL). Out of the total cases of ER + AKI, 96.92% were in ultra-endurance runners. There were inconsistences between studies in diagnosis criteria for ER and AKI, which represented a difficulty in the interpretation of the data. Increased levels of muscle and kidney injury immediately after endurance events were reported, but after 5.86 days these levels usually returned to baseline. There is a lack of knowledge around the potential of repeated ER and AKI predisposing to long-term chronic kidney disease. More accurate markers for subclinical and functional AKI diagnosis are needed in the analysis of kidney health after endurance events. ER and AKI are serious clinical problems with significant morbidity. Further research may be in order to help define future prevention strategies.

Muscle and kidney injury in endurance athletes is worrying for health, and its relationship with physical external workload (eWL) needs to be explored. This study aimed to analyze which eWL indexes have more influence on muscle and kidney injury biomarkers. 20 well-trained trail runners (age = 38.95 ± 9.99 years) ran ~35.27 km (thermal-index = 23.2 ± 1.8 °C, cumulative-ascend = 1815 m) wearing inertial measurement units (IMU) in six different spots (malleolus peroneus [MPleft/MPright], vastus lateralis [VLleft/VLright], lumbar [L1–L3], thoracic [T2–T4]) for eWL measuring using a special suit. Muscle and kidney injury serum biomarkers (creatin-kinase [sCK], creatinine (sCr), ureic-nitrogen (sBUN), albumin [sALB]) were assessed pre-, -post0h and post24h. A principal component (PC) analysis was performed in each IMU spot to extract the main variables that could explain eWL variance. After extraction, PC factors were inputted in multiple regression analysis to explain biomarkers delta change percentage (Δ%). sCK, sCr, sBUN, sALB presented large differences (p < 0.05) between measurements (pre < post24h < post0h). PC’s explained 77.5–86.5% of total eWL variance. sCK Δ% was predicted in 40 to 47% by L1–L3 and MPleft; sCr Δ% in 27% to 45% by L1–L3 and MPleft; and sBUN Δ% in 38%-40% by MPright and MPleft. These findings could lead to a better comprehension of how eWL (impacts, player load and approximated entropy) could predict acute kidney and muscle injury. These findings support the new hypothesis of mechanical kidney injury during trail running based on L1–L3 external workload data.

CrossFit is high-intensity interval training involving routines called ‘workouts of the day’ (WOD). The aim of the present study is to analyse biochemical parameters and physical performance after two modalities of CrossFit WODs, and to evaluate 48-hour recovery. Twelve trained CrossFit practitioners (age: 30.4 ± 5.37 years; VO2max: 47.8 ± 3.63 ml/min/kg; 1RM Power Clean: 93.2 ± 7.62 kg) participated in the study. A crossover design was applied, and participants completed two modalities of WODs on separate days: WOD1 (as many rounds as possible) and WOD2 (rounds for time). Blood lactate, ratings of perceived exertion and heart rate were measured to determine the intensity of training sessions. Biochemical parameters and physical performance were evaluated before, immediately after, 24 hours after and 48 hours after exercise. There were significant differences in intensity between WOD1 and WOD2 (lactate: 13.3±1.87 vs. 18.38±2.02 mmol/L, heart rate mean: 127.6±11.1 vs. 159.8±12.1 bpm), and blood glucose concentrations were significantly higher after WOD2 (135.4 ± 19.6 vs. 167.4±19.6 mg/dL). After exercise, WOD1 and WOD2 caused significant increases of hepatic transaminases, creatine phosphokinase and blood glucose, as well as a large decrease in the physical performance evaluated by the plank test. All these values returned to baseline by 48 hours after exercise. Both WODs caused metabolic and muscular stress, as well as a decrease in physical performance. All the levels recovered at 48 hours, so the stress caused by CrossFit WODs did not induce a pathological state.

Background: The relative age effect is essential throughout all of the talent selection processes in sports, especially during adolescence, which leaves fewer athletes within each cohort that are born late in the selected year. The aim of the present study was to examine the role of relative age in anthropometric and physical performance characteristics of youth handball players by gender. Methods: The sample that was selected included 47 participants (male n = 23, female n = 24). The data collection included anthropometric, body compositions parameters, and physical performance levels. Results: There was a significantly higher representation of players in the first semester in comparison with the second semester, for all of the gender groups, except for the selected male players. In males, statistically significant differences were found in height, sitting height, weight, wingspan, arm and leg circumferences, and in throws speed (in support and in suspension) between those players that were born in the first and second semester. Conclusion: The results confirmed an effect of relative age in the players born in 2002 that were selected to participate in the Spanish Championship, which was different for males and females. In spite of this effect, which only appeared in females, significant differences in the anthropometric and physical conditions appeared in the male players.

Both cold water immersion CWI protocols are effective in improving recovery in basketball players.