Are Metabolic Power Distribution and Accelerometer-Based Global Positioning System Variables Associated With Odds Ratios of Noncontact Injuries in Professional Soccer Players?

ABSTRACT: Nobari, H, Alves, AR, Abbasi, H, Khezri, D, Zamorano, AD, and Bowman, TG. Are metabolic power distribution and accelerometer-based GPS variables associated with odds ratios of noncontact injuries in professional soccer players? J Strength Cond Res 37(9): 1809-1814, 2023-The present study was intended to i) investigate the relationship between metabolic power average (MPA), acceleration (AcZ) and deceleration (DcZ) zones, and their differences (Δ) on 3 load levels with noncontact injuries in professional players throughout a full soccer season and ii) to analyze the injury risk associated between high-load versus low-load levels for each of the aforementioned parameters with odds ratios (OR) and relative risk (RR), respectively. Twenty-one professional soccer players (age = 28.3 ± 3.9 years) were monitored during a full season (48 weeks) through global positioning system (GPS). A relationship between MPA and accelerometer-based GPS, mainly in explosive actions (i.e., AcZs and DcZs), was found. A higher incidence of injuries in the high-load weeks compared with the low-load weeks were reported (mainly in MPA, AcZ1, AcZ2, and DcZ3 variables). Moreover, significant means of OR (mean = 4.3) and RR (mean = 2.6) of noncontact injuries were established in intense periods with higher metabolic load (i.e., power accelerations, AcZ1, x2 = 0.022). Our results may be useful for coaches, sports scientists, and researchers regarding the optimization of the athletes' performance, as well as providing insights about the impact of intense exercise.

Investigation of obesity, eating behaviors and physical activity levels living in rural and urban areas during the covid-19 pandemic era: a study of Turkish adolescent.

BACKGROUND: The purpose of this study was to determine the eating behaviors, obesity and physical activity status of children of similar ages living in rural and urban areas and to examine these relationships during the coronavirus disease (COVID-19) pandemic process. METHOD: The research was conducted using the scanning model. The research group consists of children living in rural and urban areas in Turkey. The sample of the study consists of a total of 733 adolescent participants, 351 females (47.9%) and 382 males (52.1%). After anthropometric measurements were made, the Physical Activity Questionnaire for older children and the Yale Food Addiction Scale for children 2.0 were used to determine the food addiction and physical activity status of children during the COVID19 pandemic process. Since the groups were homogeneously distributed, independent samples t-test and Pearson correlation test were used. RESULT: In terms of food addiction and physical activity levels, children living in the urban have higher scores than children living in rural areas. In addition, children living in the urban were taller and have higher body mass values than those in rural areas. In terms of physical activity level and food addiction levels, while girls living in the urban had higher activity levels than those living in rural areas, no statistically significant difference was found between the physical activity levels of boys. When evaluated in terms of general and gender, it was determined that children living in rural areas were overweight and obese at a higher rate. Obese children had higher levels of food addiction and lower physical activity levels than non-obese children. CONCLUSION: In order to prevent childhood obesity, the level of food addiction should be reduced as well as increasing the level of physical activity. This study is limited in terms of cross-sectional evaluation. Future research can experimentally reveal how much obesity is reduced by methods such as exercise and diet interventions.

Effects of Chronological Age, Relative Age, and Maturation Status on Accumulated Training Load and Perceived Exertion in Young Sub-Elite Football Players.

The aims of this study were 1) to analyze the influence of chronological age, relative age, and biological maturation on accumulated training load and perceived exertion in young sub-elite football players and 2) to understand the interaction effects amongst age grouping, maturation status, and birth quartiles on accumulated training load and perceived exertion in this target population. A 6-week period (18 training sessions and 324 observation cases) concerning 60 young male sub-elite football players grouped into relative age (Q1 to Q4), age group (U15, U17, and U19), and maturation status (Pre-peak height velocity (PHV), Mid-PHV, and Post-PHV) was established. External training load data were collected using 18 Hz global positioning system technology (GPS), heart-rate measures by a 1 Hz short-range telemetry system, and perceived exertion with total quality recovery (TQR) and rating of perceived exertion (RPE). U17 players and U15 players were 2.35 (95% CI: 1.25-4.51) and 1.60 (95% CI: 0.19-4.33) times more likely to pertain to Q1 and Q3, respectively. A negative magnitude for odds ratio was found in all four quartile comparisons within maturation status (95% CI: 6.72-0.64), except for Mid-PHV on Q2 (95% CI: 0.19-4.33). Between- and within-subject analysis reported significant differences in all variables on age group comparison measures (F = 0.439 to 26.636, p = 0.000 to 0.019, η2 = 0.003-0.037), except for dynamic stress load (DSL). Between-subject analysis on maturity status comparison demonstrated significant differences for all training load measures (F = 6.593 to 14.424, p = 0.000 to 0.037, η2 = 0.020-0.092). Interaction effects were found for age group x maturity band x relative age (Λ Pillai's = 0.391, Λ Wilk's = 0.609, F = 11.385, p = 0.000, η2 = 0.391) and maturity band x relative age (Λ Pillai's = 0.252, Λ Wilk's = 0.769, F = 0.955, p = 0.004, η2 = 0.112). Current research has confirmed the effects of chronological age, relative age, and biological maturation on accumulated training load. Perceived exertion does not seem to show any differences concerning age group or maturity status. Evidence should be helpful for professionals to optimize the training process and young football players' performance.

Influence of 2D:4D ratio on fitness parameters and accumulated training load in elite youth soccer players.

BACKGROUND: Digit ratio (2D:4D) characterized by the length of the second digit (2D) divided by the length of the fourth digit (4D), is a powerful marker of athletic performance. Some studies showed a negative correlation between 2D:4D ratio and sports performances. OBJECTIVES: The purpose of the present study was three-fold: (1) to analyze the influence of anthropometric and 2D:4D ratio on variations of accumulated training load (ATL) and fitness parameters: maximal oxygen uptake (V̇O2max), countermovement jump (CMJ), isometric muscular strength of the knee extensor for hamstring (ISH) and flexor for quadriceps (ISQ) muscles; along three stages of evaluation of soccer players based on playing positions; (2) to analyze the correlations between 2D:4D ratio and aforementioned parameters; and (3) to investigate if variance in fitness levels and ATL can explain the 2D:4D ratio. METHODS: Twenty-four elite players under 17 years were daily monitored for their rating perceived exertion and ATL across 24 weeks over the season. Soccer players have also measured in three stages for anthropometric traits and fitness parameters. RESULTS: Significant differences were observed between playing positions for body mass, goalkeepers had higher body mass compared to centre-midfielder and winger players. Moreover, there were significant differences in ATL between early-season to mid-season in goalkeepers (P = 0.032). The 2D:4D ratio (left and right) shown largely and negatively association with muscular strength (ISQ: r = - 0.80; r = - 0.78, P ≤ 0.001, ISH: r = - 0.63; r = - 0.62, P = 0.001, respectively) and VO2max changes (r = - 0.55, P = 0.005; r = - 0.50, P = 0.013, respectively); lastly, both 2D:4D ratio significantly predicted changes in muscular strength and VO2max in young soccer players. CONCLUSIONS: Goalkeepers tended to have higher body mass compared to centre-midfielder and winger players; and 2D:4D ratio revealed a mighty predictor of physical fitness changes in soccer players. Evidence should be helpful to professionals to highlight the usefulness of the 2D:4D into the identification of talent, but also to optimize young players' performance.

Association between Training Load and Well-Being Measures in Young Soccer Players during a Season.

This study aimed to analyze the correlations among weekly (w) acute workload (wAW), chronic workload (wCW), acute/chronic workload ratio (wACWR), training monotony (wTM), training strain (wTS), sleep quality (wSleep), delayed onset muscle soreness (wDOMS), fatigue (wFatigue), stress (wStress), and Hooper index (wHI) in pre-, early, mid-, and end-of-season. Twenty-one elite soccer players (age: 16.1 ± 0.2 years) were monitored weekly on training load and well-being for 36 weeks. Higher variability in wAW (39.2%), wFatigue (84.4%), wStress (174.3%), and wHI (76.3%) at the end-of-season were reported. At mid-season, higher variations in wSleep (59.8%), TM (57.6%), and TS (111.1%) were observed. Moderate to very large correlations wAW with wDOMS (r = 0.617, p = 0.007), wFatigue, wStress, and wHI were presented. Similarly, wCW reported a meaningful large association with wDOMS (r = 0.526, p < 0.001); moderate to very large associations with wFatigue (r = 0.649, p = 0.005), wStress, and wHI. Moreover, wTM presented a large correlation with wSleep (r = 0.515, p < 0.001); and a negatively small association with wStress (r = -0.426, p = 0.003). wTS showed a small to large correlation with wSleep (r = 0.400, p = 0.005) and wHI; also, a large correlation with wDOMS (r = 0.556, p = 0.028) and a moderate correlation with wFatigue (r = 0.343, p = 0.017). Wellness status may be considered a useful tool to provide determinant elite players' information to coaches and to identify important variations in training responses.

Associations Between Variations in Accumulated Workload and Physiological Variables in Young Male Soccer Players Over the Course of a Season.

This study sought to analyze the relationship between in-season training workload with changes in aerobic power (VO2m ax ), maximum and resting heart rate (HR max and HR rest ), linear sprint medium (LSM), and short test (LSS), in soccer players younger than 16 years (under-16 soccer players). We additionally aimed to explain changes in fitness levels during the in-season through regression models, considering accumulated load, baseline levels, and peak height velocity (PHV) as predictors. Twenty-three male sub-elite soccer players aged 15.5 ± 0.2 years (PHV: 13.6 ± 0.4 years; body height: 172.7 ± 4.2 cm; body mass: 61.3 ± 5.6 kg; body fat: 13.7% ± 3.9%; VO2m ax : 48.4 ± 2.6 mL⋅kg-1⋅min-1), were tested three times across the season (i.e., early-season (EaS), mid-season (MiS), and end-season (EnS) for VO2m ax , HR max , LSM, and LSS. Aerobic and speed variables gradually improved over the season and had a strong association with PHV. Moreover, the HR max demonstrated improvements from EaS to EnS; however, this was more evident in the intermediate period (from EaS to MiS) and had a strong association with VO2m ax . Regression analysis showed significant predictions for VO2m ax [F ( 2, 20) = 8.18, p ≤ 0.001] with an R 2 of 0.45. In conclusion, the meaningful variation of youth players' fitness levels can be observed across the season, and such changes can be partially explained by the load imposed.

Variations of estimated maximal aerobic speed in children soccer players and its associations with the accumulated training load: Comparisons between non, low and high responders.

The aim of this study was twofold: (i) to examine the variations of estimated maximal aerobic speed between non, low and high responders and (ii) to analyze the relationships between accumulated training load parameters and variations of maximal aerobic speed in children soccer players. Forty-four male soccer players were assessed three times during the early and mid-season (second to fifth month of the season) and were monitored daily over the period of analysis using the rating of perceived exertion (RPE), recording the training duration (in min) and calculating the session-RPE (sRPE). Pairwise comparisons revealed that maximal aerobic speed (MAS) was greater for the third assessment than the first (p-value [p] = 0.003; standardized effect of Cohen [d] = 0.355) and second (p = 0.013; d = 0.193) assessments. Large correlations were found between MAS and accumulated RPE, accumulated time, and accumulated sRPE. Moreover, non, low and high responders differed in ΔMAS (p<0.001) with the last group presenting the largest improvement in MAS. Results suggest that children with lower MAS baseline levels will improve more this capacity over the early and mid-season period compared to children with better baseline levels. Moreover, associations between accumulated training load and MAS were found, suggesting that the training effort can be related with aerobic capacity changes.