Rapid muscle activation changes across a competitive collegiate female soccer season

Objective:The purpose of this study was to examine the effects of a competitive soccer season on rapid activation properties of the knee extensors and flexors in Division II female soccer players.Methods:Eighteen collegiate female soccer players participated in the present study, however, due to injuries during the season a final sample of 16 players were included for study analysis. Participants performed two maximal voluntary isometric contractions (MVICs) of the knee extensors and flexors before, during, and at the end of a competitive college soccer season. Electromyography root mean square (EMG RMS; µV), rate of EMG rise (RER; %Peak EMG•s^-1), and electromechanical delay (EMD; ms) were examined on both legs for the knee extensors and flexors.Results:EMG RMS at early time intervals (0-50, 0-100, and 50-100 ms) and RER at 0-75 ms for the knee extensors and flexors significantly increased from the pre-season to the end of the season (P≤0.010-0.026, η²=0.36-0.81). EMD of the knee flexors significantly decreased at the mid-season and the end of the season compared to the pre-season (P<0.001, η²=0.95).Conclusions:These findings may have important implications for monitoring improvements on thigh neuromuscular activation and developing lower extremity injury prevention strategies during a competitive collegiate female soccer season.     

Rate of torque development as a discriminator of playing level in collegiate female soccer players

Objectives:This study aimed to examine the efficacy of isometric knee extension and flexion peak torque and rate of torque development (RTD) variables to distinguish starters from non-starters in collegiate female soccer players.Methods:Eleven starters (20±2 years) and 13 non-starters (19±1 years) performed three isometric maximal voluntary contractions of the knee extensors and flexors. Peak torque, peak RTD, and RTD at 0-100 (RTD100) and 0-200 (RTD200) ms were obtained from each contraction.Results:The starters produced significantly greater (P=0.002-0.015) knee extension and flexion peak RTD, RTD100, and RTD200 values than the non-starters. There were no significant differences (P>0.050) between the starters and non-starters for peak torque. Discriminant analysis revealed thresholds of 9.36, 7.98, and 6.97 Nm⋅s^-1⋅kg^-1 for knee extension RTD200 and knee flexion peak RTD and RTD100, respectively. These thresholds showed 81.8% sensitivity and 76.9 to 92.3% specificity for identifying playing group membership.Conclusions:Our findings indicate that RTD may be a better parameter than peak torque at differentiating between playing level in collegiate female soccer players. The discriminant analysis thresholds for the RTD variables demonstrated good sensitivity and specificity, and therefore, may be used as indices to identify players with a high degree of soccer playing ability.     

Estimating excess post-exercise oxygen consumption using multiple linear regression in healthy Korean adults: a pilot study

[Purpose]This pilot study aimed to develop a regression model to estimate the excess post-exercise oxygen consumption (EPOC) of Korean adults using various easy-to-measure dependent variables.[Methods]The EPOC and dependent variables for its estimation (e.g., sex, age, height, weight, body mass index, fat-free mass [FFM], fat mass, % body fat, and heart rate_sum [HR_sum]) were measured in 75 healthy adults ( 31 males, 44 females). Statistical analysis was performed to develop an EPOC estimation regression model using the stepwise regression method.[Results]We confirmed that FFM and HR_sum were important variables in the EPOC regression models of various exercise types. The explanatory power and standard errors of estimates (SEE) for EPOC of each exercise type were as follows: the continuous exercise (CEx) regression model was 86.3% (R²) and 85.9% (adjusted R²), and the mean SEE was 11.73 kcal, interval exercise (IEx) regression model was 83.1% (R²) and 82.6% (adjusted R²), while the mean SEE was 13.68 kcal, and the accumulation of short-duration exercise (AEx) regression models was 91.3% (R²) and 91.0% (adjusted R²), while the mean SEE was 27.71 kcal. There was no significant difference between the measured EPOC using a metabolic gas analyzer and the predicted EPOC for each exercise type.[Conclusion]This pilot study developed a regression model to estimate EPOC in healthy Korean adults. The regression model was as follows: CEx = -37.128 + 1.003 × (FFM) + 0.016 × (HR_sum), IEx = -49.265 + 1.442 × (FFM) + 0.013 × (HR_sum), and AEx = -100.942 + 2.209 × (FFM) + 0.020 × (HR_sum).     

Outcome of transcatheter aortic valve replacement in patients over 85 years of age versus patients aged 85 and younger

IntroductionThe Dutch general population is aging rapidly. Many of these patient are fit and eligible for TAVR. However, studies on outcome in older versus younger patients are scant.Material and methodsA single-centre retrospective study comparing patients older and younger than age 85 on outcome.Results190 patients underwent TAVR: 136 were aged 85 or younger (U85), 54 were older than 85 (O85). The U85 group had more men (U85: 71 [52.2%] vs O85: 19 [35.2%]; p = 0.034), a higher incidence of diabetes (U85: 36 [26.5%] vs O85: 3 [5.6%]; p = 0.001) and atrial fibrillation (U85: 35 [25.7%] vs O85: 5 [9.3%]; p = 0.03) and a higher body mass index (U85: 27.5 [± 5.24] vs O85: 26 [± 3.78]; p = 0.027). In the O85 group there was a lower estimated glomerular filtration rate (O85: 50.28 [± 15.32] ml/min vs U85: 65.25 [± 29.97] ml/min; p = 0.012). There was no difference in 30-day mortality (U85: 6 [4.4%] vs O85: 3 [5.6%]) and 1‑year mortality (U85 9 [6.6%] vs O85 3 [5.6%]) (p = 0.521). There was an equal amount of new onset permanent left bundle branch block (U85: 38 [27.9%] vs O85: 14 [25.9%]; p = 0.896) and permanent pacemaker implantation (U85: 28 [20.6%] vs O85: 28 [20.6%]; p = 0.748). There was no difference in bleeding events (p = 0.469), vascular complications (p = 0.195) or moderate/severe regurgitation (p = 0.972). The U85 group had a slightly longer admission duration (U85 6.29 [± 5.289] days vs O85 5.98 [± 3.328] days (p = 0.037)).ConclusionTAVR in patients over 85 years of age has excellent outcome, comparable to those aged 85 and younger.     

Improving hydration in elite male footballers during a national team training camp – an observational case study

[Purpose] The purpose of this study was to (i) assess hydration levels in elite male football players during a national team training camp before and during qualifying matches, (ii) evaluate the effect of coaching strategies for hydration based on feedback from hydration monitoring, and (iii) assess possible relationships between hydration status and training load or wellness markers.[Methods] Thirty-one male players (age 27±4 yrs; height 185±6 cm; weight 82.9±6.7 kg; body fat 10.4±2.3%) representing a national team from the Union of European Football Associations (UEFA) participated. The players were studied during three different national team training camps related to the UEFA Nations League tournament. Urine specific gravity (U_SG) was measured to assess hydration status. During all camps, the players were actively coached on improving strategies for hydration and given individual feedback on their test results. The training load was measured using GPS technology, and wellness questionnaires were completed.[Results] U_SG decreased progressively and significantly (p<0.005) during camp 1 and hydration status improved over the three camps, with fewer dehydrated and more well-hydrated players identified during the last part of camp 3. Significantly (p<0.05) higher U_SG values were observed 2 days prior to a match (MD-2) than on match day (MD); consequently, 52% of the players were dehydrated on MD-2 and only 6% on MD. No correlations were observed between hydration status and training load or wellness markers.[Conclusion] Dehydration is a challenge in elite male football, but continuous monitoring of hydration status and coaching on hydration strategies can lead to major improvements and reduce the degree of dehydration.     

Differences of energy intake and energy expenditure of elite Taekwondo players receiving summer vs. winter intensive training

[Purpose]

This study aimed to evaluate the energy expenditure and energy intake as an experiment of energy balance of elite Taekwondo players receiving summer vs. winter intensive training.

[Methods]

The summer training group (STG, n = 15) and the winter training group (WTG, n = 18) wore an accelerometer for the measurement of energy expenditure and maintained a daily dietary record for measurement of energy intake, for seven consecutive days during summer or winter intensive training.

[Results]

The total energy expenditure (TEE) (834.1 kcal, p < .001), the total counts (1,867 counts, p = .038), and the energy expenditure during moderate (384.6 kcal, p < .001) and vigorous activity (351.8 kcal, p < .001) were significantly lower in the STG than in the WTG. On the other hand, the macronutrient intake showed that intake of energy (902.7 kcal, p < .001), carbohydrates (82.6g, p < .001), and protein (93.9g, p < .001) in the STG were significantly lower than those of the WTG. When comparing TEE and total energy intake, the STG consumed 902.7 kcal less as energy than the WTG, while the STG performed 834.1 kcal more as TEE than that of the WTG.

[Conclusion]

In conclusion, both of the summer and winter intensive training are not proper for energy balance condition. Therefore, to promote the optimal energy balance during the summer or winter intensive training period, a training and sports nutrition program based on the amount of energy expenditure and energy intake for Taekwondo players should be considered.     

Reliability and validity of a modified Illinois change-of-direction test with ball dribbling speed in young soccer players

The purpose of this study was to assess test-retest reliability, discriminative and criterion-related validity of the modified Illinois change-of-direction (CoD) test with ball dribbling-speed (ICODT-BALL) in young soccer players of different biological maturity and playing levels. Sixty-five young male soccer players (11.4 ± 1.2 years) participated in this study. The participants were classified according to their biological maturity (pre- and circumpeak height velocity [PHV]) and playing-level (elite and amateur players). During the test-retest time period of two weeks, the following tests were performed during week one and as retest during week two: ICODT-BALL, ICODT, 4 × 9-m shuttle-run, countermovement-jump, triple-hop-test, maximum-voluntary isometric-contraction of back-extensors, Stork, Y-Balance, 10 and 30-m sprints. The ICODT-BALL showed excellent relative (r = 0.995, p < 0.001; ICC = 0.993) and absolute (SEM < 5%; SEM < SWCs_{(0.2, 0.6, 1.2)}) reliability. The circum-PHV (22.8 ± 1.7-s) and elite (22.5 ± 0.9-s) players showed better ICODT-BALL performance than their pre-PHV (24.2 ± 2.5-s) and amateur (25.1 ± 2.8-s) counterparts (p = 0.028 and p < 0.001, respectively). The ICODT-BALL showed “very good” (AUC = 0.81) discriminant validity when comparing the elite and amateur players, and “moderate” (AUC = 0.67) discriminant validity when compared to pre-PHV and circum-PHV boys. ICODT-BALL demonstrated “large” positive associations with the ICODT (r = 0.65; 41.8% shared-variance) and sprint tests (r ≥ 0.52; 27.3 to 34.8% shared-variance). In addition, results showed “moderate” negative associations between ICODT-BALL and strength, and power measures, as well as a “small” negative relationship with balance tests. In conclusion, the ICODT-BALL is a valid and reliable test to evaluate the ability to quickly change directions while ball dribbling in young soccer players. Therefore, practitioners can use the ICODT-BALL as a tool for talent identification.     

Analysis of Jumping-Landing Manoeuvers after Different Speed Performances in Soccer Players

PurposeRunning at high speed and sudden change in direction or activity stresses the knee. Surprisingly, not many studies have investigated the effects of sprinting on knee’s kinetics and kinematics of soccer players. Hence, this study is aimed to investigate indices of injury risk factors of jumping-landing maneuvers performed immediately after sprinting in male soccer players.MethodsTwenty-three collegiate male soccer players (22.1±1.7 years) were tested in four conditions; vertical jump (VJ), vertical jump immediately after slow running (VJSR), vertical jump immediately after sprinting (VJFR) and double horizontal jump immediately after sprinting (HJFR). The kinematics and kinetics data were measured using Vicon motion analyzer (100Hz) and two Kistler force platforms (1000Hz), respectively.ResultsFor knee flexion joint angle, (p = 0.014, η = 0.15) and knee valgus moment (p = 0.001, η = 0.71) differences between condition in the landing phase were found. For knee valgus joint angle, a main effect between legs in the jumping phase was found (p = 0.006, η = 0.31), which suggests bilateral deficit existed between the right and left lower limbs.ConclusionIn brief, the important findings were greater knee valgus moment and less knee flexion joint angle proceeding sprint (HJFR & VJFR) rather than no sprint condition (VJ) present an increased risk for knee injuries. These results seem to suggest that running and sudden subsequent jumping-landing activity experienced during playing soccer may negatively change the knee valgus moment. Thus, sprinting preceding a jump task may increase knee risk factors such as moment and knee flexion joint angle.     

Body mass index and relative handgrip strength are associated with the prevalence of hypertension in Korean elderly: Korean national fitness assessment in 2019

[Purpose]This study aimed to analyze the prevalence of hypertension according to the body mass index (BMI) and relative handgrip strength (RHGS) among elderly individuals in Korea. [Methods]We analyzed the data of 44,183 Korean elderly individuals over 65 years old (men: n = 15,798, age = 73.31 ± 5.04 years, women: n = 28,385, age = 72.14 ± 5.04 years) obtained from the Korean National Fitness Assessment in 2019. All the participants were categorized into three groups according to the BMI and RHGS; additionally, one-way ANOVA and logistic regression analysis were performed. [Results]Overweight (men: 1.16 odds ratio [OR] 1.06–1.26, 95% confidence interval [CI]; women: 1.15 OR, 1.07–1.23 95% CI) and obese (men: 1.54 OR, 1.42–1.66 95% CI; women: 1.44 OR, 1.36–1.53 95% CI) elderly individuals showed a higher prevalence of hypertension than elderly individuals with normal weight, after controlling for age. In men, a lower RHGS was associated with a higher prevalence of hypertension after controlling for age (weak RHGS: 1.09 OR, 1.00–1.17 95% CI; middle RHGS: 1.21 OR, 1.12–1.31 95% CI vs. strong RHGS). [Conclusion]A higher BMI was associated with the prevalence of hypertension in the elderly Korean population. In addition, a lower RHGS was associated with the prevalence of hypertension in elderly Korean men.     

Resting Energy Expenditure Prediction in Recreational Athletes of 18–35 Years: Confirmation of Cunningham Equation and an Improved Weight-Based Alternative

Introduction

Resting energy expenditure (REE) is expected to be higher in athletes because of their relatively high fat free mass (FFM). Therefore, REE predictive equation for recreational athletes may be required. The aim of this study was to validate existing REE predictive equations and to develop a new recreational athlete specific equation.

Methods

90 (53M, 37F) adult athletes, exercising on average 9.1±5.0 hours a week and 5.0±1.8 times a week, were included. REE was measured using indirect calorimetry (Vmax Encore n29), FFM and FM were measured using air displacement plethysmography. Multiple linear regression analysis was used to develop a new FFM-based and weight-based REE predictive equation. The percentage accurate predictions (within 10% of measured REE), percentage bias, root mean square error and limits of agreement were calculated.

Results

The Cunningham equation and the new weight-based equation and the new FFM-based equation performed equally well. De Lorenzo''s equation predicted REE less accurate, but better than the other generally used REE predictive equations. Harris-Benedict, WHO, Schofield, Mifflin and Owen all showed less than 50% accuracy.

Conclusion

For a population of (Dutch) recreational athletes, the REE can accurately be predicted with the existing Cunningham equation. Since body composition measurement is not always possible, and other generally used equations fail, the new weight-based equation is advised for use in sports nutrition.     

Comparison of energy expenditure and substrate oxidation between walking and running in men and women

[Purpose]The present study compared energy metabolism between walking and running at equivalent speeds during two incremental exercise tests.[Methods]Thirty four university students (18 males, 16 females) were recruited. Each participant completed two trials, consisting of walking (Walk) and running (Run) trials on different days, with 2-3 days apart. Exercise on a treadmill was started from initial stage of 3 min (3.0 k/m in Walk trial, 5.0 km/h in Run trial), and the speed for walking and running was progressively every minute by 0.5 km/h. The changes in metabolic variables, heart rate (HR), and rating of perceived exertion (RPE) during exercise were compared between the trials.[Results]Energy expenditure (EE) increased with speed in each trial. However, the Walk trial had a significantly higher EE than the Run trial at speeds exceeding 92 ± 2 % of the maximal walking speed (MWS, p < 0.01). Similarly, carbohydrate (CHO) oxidation was significantly higher in the Walk trial than in the Run trial at above 92 ± 2 %MWS in males (p < 0.001) and above 93 ± 1 %MWS in females (p < 0.05).[Conclusion]These findings suggest that EE and CHO oxidation during walking increase non-linearly with speed, and walking at a fast speed causes greater metabolic responses than running at the equivalent speed in young participants.     

Validity and Reliability of New Agility Test among Elite and Subelite under 14-Soccer Players

Background

Agility is a determinant component in soccer performance. This study aimed to evaluate the reliability and sensitivity of a “Modified Illinois change of direction test” (MICODT) in ninety-five U-14 soccer players.

Methods

A total of 95 U-14 soccer players (mean ± SD: age: 13.61±1.04 years; body mass: 30.52±4.54 kg; height: 1.57±0.1 m) from a professional and semi-professional soccer academy, participated to this study. Sixty of them took part in reliability analysis and thirty-two in sensitivity analysis.

Results

The intraclass correlation coefficient (ICC) that aims to assess relative reliability of the MICODT was of 0.99, and its standard error of measurement (SEM) for absolute reliability was <5% (1.24%). The MICODT’s capacity to detect change is “good”, it’s SEM (0.10 s) was ≤ SWC (0.33 s). The MICODT is significantly correlated to the Illinois change of direction speed test (ICODT) (r = 0.77; p<0.0001). The ICODT’s MDC₉₅ (0.64 s) was twice about the MICODT’s MDC₉₅ (0.28 s), indicating that MICODT presents better ability to detect true changes than ICODT. The MICODT provided good sensitivity since elite U-14 soccer players were better than non-elite one on MICODT (p = 0.005; d_z = 1.01 [large]). This was supported by an area under the ROC curve of 0.77 (CI 95%, 0.59 to 0.89, p<0.0008). The difference observed in these two groups in ICODT was not statistically significant (p = 0.14; d_z = 0.51 [small]), showing poor discriminant ability.

Conclusion

MICODT can be considered as more suitable protocol for assessing agility performance level than ICODT in U-14 soccer players.     

Biological maturation influences selection process in youth elite soccer players

This study examined the influence of birth date, salivary testosterone [sT] concentration, sexual maturity status, and general strength on the selection process of an elite Brazilian soccer club during a 12-month period, which was a 2^nd phase of a 24-month selection process. The stature, body mass, sT, sexual maturity status [Tanner scale], and hand grip strength were assessed for 143 players during 2 weeks. From these 143 players, 100 players were dismissed [DIS] and 43 players were selected to integrate the club’s under-14 squad. Following 1-year training period, the under-14 team was assembled with 9 players designated as starters [STA], and then, comparisons were conducted taking into account a group of non-starters (selected; SEL = 34 players) and STA (n = 09). The DIS, SEL, STA players, and reference population, were compared for birth distribution. A greater proportion of players was born in the first trimester in the STA [75.0%], SEL [57.1%] and DIS [50.0%] groups compared to the reference population [25.8%]. One-way ANOVA showed a higher sT for STA group [516.0 ± 129.9 pmol·L^-1], compared to SEL [415.5 ± 117.9 pmol·L^-1] and DIS groups [390.9 ± 84.9 pmol·L^-1; p = 0.003), and Kruskall-Wallis test showed a higher gonadal development for STA compared to DIS [p = 0.001]. The current findings suggest a strong influence of birth date and biological maturation on young soccer players selection process. Soccer coaches should consider these influences when making decisions about player selection of elite youth players.     

Sprint Conditioning of Junior Soccer Players: Effects of Training Intensity and Technique Supervision

The aims of the present study were to compare the effects of 1) training at 90 and 100% sprint velocity and 2) supervised versus unsupervised sprint training on soccer-specific physical performance in junior soccer players. Young, male soccer players (17 ±1 yr, 71 ±10 kg, 180 ±6 cm) were randomly assigned to four different treatment conditions over a 7-week intervention period. A control group (CON, n=9) completed regular soccer training according to their teams’ original training plans. Three training groups performed a weekly repeated-sprint training session in addition to their regular soccer training sessions performed at A) 100% intensity without supervision (100UNSUP, n=13), B) 90% of maximal sprint velocity with supervision (90SUP, n=10) or C) 90% of maximal sprint velocity without supervision (90UNSUP, n=13). Repetitions x distance for the sprint-training sessions were 15x20 m for 100UNSUP and 30x20 m for 90SUP and 90UNSUP. Single-sprint performance (best time from 15x20 m sprints), repeated-sprint performance (mean time over 15x20 m sprints), countermovement jump and Yo-Yo Intermittent Recovery Level 1 (Yo-Yo IR1) were assessed during pre-training and post-training tests. No significant differences in performance outcomes were observed across groups. 90SUP improved Yo-Yo IR1 by a moderate margin compared to controls, while all other effect magnitudes were trivial or small. In conclusion, neither weekly sprint training at 90 or 100% velocity, nor supervised sprint training enhanced soccer-specific physical performance in junior soccer players.     

Metabolic and Behavioral Compensations in Response to Caloric Restriction: Implications for the Maintenance of Weight Loss

Background

Metabolic and behavioral adaptations to caloric restriction (CR) in free-living conditions have not yet been objectively measured.

Methodology and Principal Findings

Forty-eight (36.8±1.0 y), overweight (BMI 27.8±0.7 kg/m²) participants were randomized to four groups for 6-months; Control: energy intake at 100% of energy requirements; CR: 25% calorie restriction; CR+EX: 12.5% CR plus 12.5% increase in energy expenditure by structured exercise; LCD: low calorie diet (890 kcal/d) until 15% weight reduction followed by weight maintenance. Body composition (DXA) and total daily energy expenditure (TDEE) over 14-days by doubly labeled water (DLW) and activity related energy activity (AREE) were measured after 3 (M3) and 6 (M6) months of intervention. Weight changes at M6 were −1.0±1.1% (Control), −10.4±0.9% (CR), −10.0±0.8% (CR+EX) and −13.9±0.8% (LCD). At M3, absolute TDEE was significantly reduced in CR (−454±76 kcal/d) and LCD (−633±66 kcal/d) but not in CR+EX or controls. At M6 the reduction in TDEE remained lower than baseline in CR (−316±118 kcal/d) and LCD (−389±124 kcal/d) but reached significance only when CR and LCD were combined (−351±83 kcal/d). In response to caloric restriction (CR/LCD combined), TDEE adjusted for body composition, was significantly lower by −431±51 and −240±83 kcal/d at M3 and M6, respectively, indicating a metabolic adaptation. Likewise, physical activity (TDEE adjusted for sleeping metabolic rate) was significantly reduced from baseline at both time points. For control and CR+EX, adjusted TDEE (body composition or sleeping metabolic rate) was not changed at either M3 or M6.

Conclusions

For the first time we show that in free-living conditions, CR results in a metabolic adaptation and a behavioral adaptation with decreased physical activity levels. These data also suggest potential mechanisms by which CR causes large inter-individual variability in the rates of weight loss and how exercise may influence weight loss and weight loss maintenance.

Trial Registration

ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT00099151","term_id":"NCT00099151"}}NCT00099151     

Changes in physical activity and energy intake according to abdominal obesity in Korean adult men before and after COVID-19: Data from 2019 and 2020 Korea National Health and Nutrition Examination Survey (KNHANES)

[Purpose] This study aimed to investigate changes in physical activity and energy intake according to abdominal obesity in Korean adult men before and after COVID-19.[Methods] Using data from the 2019 and 2020 KNHANES, the physical activity level measured by the Global Physical Activity Questionnaire (GPAQ) the physical activity level by GPAQ, number of days of walking and strength training, aerobic exercise, and total energy, protein, fat, carbohydrate, dietary fiber, and sugar intake for a total of 2,799 participants were analyzed.[Results] There were no changes in energy intake during the pandemic. The number of days of weekly walking was higher (2019, p = 0.006; 2020, p = 0.012) and strength training was significantly higher (2019, p < 0.0001; 2020 p < 0.0001) in the non-abdominal obesity group than in the abdominal obesity group before and after COVID-19. Strength training at least once a week suppressed abdominal obesity (0.628 times in 2019, p < 0.0001; 0.605 times in 2020, p < 0.0001). In addition, even when the total energy intake and age were adjusted for, strength training influenced the suppression of abdominal obesity (0.634 times in 2019, p < 0.0001; 0.614 times in 2020, p < 0.0001).[Conclusion] Even with the change in the physical activity level, such as walking and aerobic exercise, due to the influence of social distancing measures, strength training influenced the suppression of abdominal obesity, regardless of the COVID-19 pandemic.     

Effects of hippotherapy on brain function,BDNF level,and physical fitness in children with ADHD

[Purpose]

The purpose of this study was to examine the effects of hippotherapy on brain function and levels of blood-derived neurotrophic factor (BDNF) in children with attention deficit and/or hyperactivity disorder (ADHD).

[Methods]

The hippotherapy group (HRG) included twenty children with ADHD and the control group (CG) included 19 children. All participants’ physical fitness, fMRI brain scans, and blood BDNF levels were measured at baseline and after 32 weeks of participating in hippotherapy.

[Results]

After 32 weeks of participating in hippotherapy, the body fat of the HRG was significantly decreased (-1.12 ± 4.20%) and the body fat of the CG was increased (2.38 ± 6.35%) (p=0.049). There was no significant difference of physical fitness in both groups (p>0.05). Although there was a higher decrease in the activated insular area in the HRG (-1.59 ± 0.99) than in the CG (-1.14 ± 1.41), there was no significant difference between the two groups (p>0.05) Also, there was a higher increase in the activated cerebellum area in the HRG (1.97 ± 1.45) than in the CG (1.92 ± 1.81). However, there was no significant difference between the two groups (p>0.05). BDNF levels showed an increased tendency in the HRG (166.29 ± 277.52pg) compared to the CG (21.13 ± 686.33pg); otherwise, there was not any significant difference in these blood levels between the two groups (p>0.05). It can be assumed that big individual differences in the level of ADHD in the study participants might not cause any significant results, although there might be positive changes in the brain function of children with ADHD.

[Conclusion]

Therefore, this study suggests that hippotherapy training would need to be modified and developed to increase the efficacy of hippotherapy in children with ADHD.     

A high-whey-protein diet does not enhance mechanical and structural remodeling of cardiac muscle in response to aerobic exercise in rats

[Purpose]Aerobic exercise training results in distinct structural and mechanical myocardial adaptations. In skeletal muscle, whey protein supplementation is effective in enhancing muscle adaptation following resistance exercise. However, it is unclear whether cardiac adaptation to aerobic exercise can be enhanced by systematic protein supplementation.[Methods]Twelve-week-old rats were assigned to 12 weeks of either sedentary or aerobic exercise with either a standard (Sed+Standard, Ex+Standard) or high-protein (Sed+Pro, Ex+Pro) diet. Echocardiography was used to measure cardiac structural remodeling and performance. Skinned cardiac fiber bundles were used to determine the active and passive stress properties, maximum shortening velocity, and calcium sensitivity.[Results]Aerobic training was characterized structurally by increases in ventricle volume (Ex+Standard, 19%; Ex+Pro, 29%) and myocardial thickness (Ex+Standard, 26%; Ex+-Pro, 12%) compared to that of baseline. Skinned trabecula r fiber bundles also had a greater unloaded shortening velocity (Sed+Standard, 1.04±0.05; Sed+Pro, 1.07±0.03; Ex-+Standard, 1.16±0.04; Ex+Pro, 1.18±0.05 FL/s) and calcium sensitivity (pCa₅₀: Sed+Standard, 6.04±0.17; Sed+Pro, 6.08±0.19; Ex+Standard, 6.30±0.09; Ex+Pro, 6.36±0.12) in trained hearts compared to that of hearts from sedentary animals. However, the addition of a high-protein diet did not provide additional benefits to either the structural or mechanical adaptations of the myocardium.[Conclusion]Therefore, it seems that a high-whey-protein diet does not significantly enhance adaptations of the heart to aerobic exercise in comparison to that of a standard diet.     

Reliability and Discriminative Ability of a New Method for Soccer Kicking Evaluation

The study aimed to evaluate the test–retest reliability of a newly developed 356 Soccer Shooting Test (356-SST), and the discriminative ability of this test with respect to the soccer players'' proficiency level and leg dominance. Sixty-six male soccer players, divided into three groups based on their proficiency level (amateur, n = 24; novice semi-professional, n = 18; and experienced semi-professional players, n = 24), performed 10 kicks following a two-step run up. Forty-eight of them repeated the test on a separate day. The following shooting variables were derived: ball velocity (BV; measured via radar gun), shooting accuracy (SA; average distance from the ball-entry point to the goal centre), and shooting quality (SQ; shooting accuracy divided by the time elapsed from hitting the ball to the point of entry). No systematic bias was evident in the selected shooting variables (SA: 1.98±0.65 vs. 2.00±0.63 m; BV: 24.6±2.3 vs. 24.5±1.9 m s^-1; SQ: 2.92±1.0 vs. 2.93±1.0 m s^-1; all p>0.05). The intra-class correlation coefficients were high (ICC = 0.70–0.88), and the coefficients of variation were low (CV = 5.3–5.4%). Finally, all three 356-SST variables identify, with adequate sensitivity, differences in soccer shooting ability with respect to the players'' proficiency and leg dominance. The results suggest that the 356-SST is a reliable and sensitive test of specific shooting ability in men’s soccer. Future studies should test the validity of these findings in a fatigued state, as well as in other populations.     

Cognitive Functions in Elite and Sub-Elite Youth Soccer Players Aged 13 to 17 Years

Soccer players are required to anticipate and react continuously in a changing, relatively unpredictable situation in the field. Cognitive functions might be important to be successful in soccer. The current study investigated the relationship between cognitive functions and performance level in elite and sub-elite youth soccer players aged 13–17 years. A total of 47 elite youth soccer players (mean age 15.5 years, SD = 0.9) and 41 sub-elite youth soccer players (mean age 15.2 years, SD = 1.2) performed tasks for “higher-level” cognitive functions measuring working memory (i.e., Visual Memory Span), inhibitory control (i.e., Stop-Signal Task), cognitive flexibility (i.e., Trail Making Test), and metacognition (i.e., Delis-Kaplan Executive Function System Design Fluency Test). “Lower-level” cognitive processes, i.e., reaction time and visuo-perceptual abilities, were also measured with the previous tasks. ANOVA’s showed that elite players outscored sub-elite players at the “higher-level” cognitive tasks only, especially on metacognition (p < .05). Using stepwise discriminant analysis, 62.5% of subjects was correctly assigned to one of the groups based on their metacognition, inhibitory control and cognitive flexibility performance. Controlling for training hours and academic level, MANCOVA’s showed differences in favor of the elite youth soccer players on inhibitory control (p = .001), and cognitive flexibility (p = .042), but not on metacognition (p = .27). No differences were found concerning working memory nor the “lower-level” cognitive processes (p > .05). In conclusion, elite youth soccer players have better inhibitory control, cognitive flexibility, and especially metacognition than their sub-elite counterparts. However, when training hours are taken into account, differences between elite and sub-elite youth soccer players remain apparent on inhibitory control and cognitive flexibility in contrast to metacognition. This highlights the need for longitudinal studies to further investigate the importance of “higher-level” cognitive functions for talent identification, talent development and performance in soccer.