The response of circulating omentin-1 concentration to 16-week exercise training in male children with obesity

Objectives: The purpose of the present study was to investigate the effects of the 16-week exercise training program on serum omentin-1 in relation to change in insulin resistance in obese male children.

Methods: Thirty-two obese male children, aged 9–12 years, were randomly assigned into Exercise Group (ExG; n = 16) and Control Group (CG; n = 16). ExG participated in a 16-week exercise training program which combined various forms of aerobic activities and resistance training. Body composition, body mass index (BMI), waist circumference (WC), fasting glucose and insulin, homeostasis model assessment estimate of insulin resistance (HOMA2-IR), blood lipids and serum omentin-1 were assessed before and after 16 weeks of training.

Results: Exercise training significantly decreased body mass (7.5%), BMI (7.6%), WC (4.3%), body fat % (15%), fasting insulin (18.5%), total cholesterol (TC) (5.4%), low-density lipoprotein cholesterol (LDL-C) (17%) and triglyceride (TG) (7.4%) compared to CG. Between-groups comparison showed a considerable exercise-induced upregulation in omentin-1 (ES = 89; P < 0.05) levels. Furthermore, in ExG serum omentin-1 levels were significantly increased from 24.5 ± 8.4 to 35.9 ± 9.3 ng/ml (45%; P < 0.001) after the training program, which was accompanied with significantly decreased fasting insulin (P < 0.001). The changes in omentin-1 concentrations correlated with the changes in BMI (r = ?0.67, P < 0.001), WC (r = ?0.62, P = 0.002), body fat % (r = ?0.50, P = 0.004), insulin (r = ?0.65, P = 0.001), HOMA2-IR (r = ?0.60, P = 0.004), TC (r = ?0.53, P = 0.004) and LDL-C (r = ?0.51, P = 0.004) in ExG. BMI (β = ?0.50, P = 0.009) and fasting insulin (β = ?0.54, P = 0.006) changes were found to be independent predictors of omentin-1 increment in multiple regression analysis.

Conclusion: Exercise training resulted in a significant increase in serum omentin-1 concentrations in children with obesity. The ?ndings suggest that exercise-induced changes in omentin-1 may be associated with the bene?cial effects of exercise on reduced insulin and weight lost.     

Strength adaptation to squat exercise is different between Caucasian and South Asian novice exercisers

This study compared the progression of muscular strength (MS) adaptation between age-matched Caucasian (CAUC) and South Asian (SOU) men during 6 weeks (3× week^?1) of resistance training. MS was determined pre and post intervention by 3-repetition maximum (3RM) strength tests, and data were analysed using repeated measures ANOVA. Pre-intervention upper and lower body 3RM were similar between groups and both upper and lower body 3RM increased in CAUCs (P < .001) and SOUs (P < .001) following resistance training. However, lower body strength adaptation (3RM) was higher in CAUCs compared with SOUs (P = .002). There was a significant group × time interaction in strength progression of the squat exercise (P = 0.03) from session 7 through to 18 (completion). The present study offers novel but provisional data that lower body strength adaptation is slower in SOU than CAUC men despite comparable adaptation to upper body strength.     

Rapid weight gain in professional boxing and correlation with fight decisions: analysis from 71 title fights

Objectives: Boxing is a sport where athletes compete in several weight categories. Professional boxers typically dehydrate to cut their weight for the weigh-in (24 h before the contest) and then rehydrate before the fight. The International Boxing Federation (IBF) mandates a second weigh-in 12 h before the fight. Our objectives were: 1) To quantify the weight gain (WG) from the 1st to the 2nd weigh-in; 2) to investigate whether rapid WG affects boxing performance (win/loss rate) and 3) whether weight discrepancy (WD) 15 between boxers exposes them to increased health risks (rate of fights ended before time limit).

Methods: From official weigh-in reports of 71 IBF fights (142 fighters) the following data were gathered/calculated for each boxer: age, weight division, 1st weight, 2nd weight, WG between weigh-ins (kg and %), WD between opponents, and fight decision.

Results: Between the weigh-ins, the average WG was 2.52 ± 1.37 kg (range ?0.3/6.4 kg) and 3.8 ± 2.2% of the initial body weight (range ?0.4/9.3%) and the average WD 1.94 ± 1.50 kg (maximum 7.10 kg). Both WG and WD did not affect match outcomes. We observed tendencies for higher loss rate among boxers gaining more weight, and for higher victory rate in boxers with larger WD, however without reaching significance. A significant negative correlation was found between the 1st weight and the WG, both in absolute (r = ?0.278, p = 0.001) and relative value (r = ?0.497, p < 0.0001).

Conclusions: Although correlations between WG, WD and boxing performance were not found, single cases with an alarming high WG and WD were noted.     

The influence of youth soccer players’ sprint performance on the different sided games’ external load using GPS devices

ABSTRACT

The aims of this study are 1) to compare sided games’ (SGs) external responses encountered by players according to pitch size and to 2) examine the relationships between sprint performance and SGs’ external physical responses. Twenty soccer players under 15 years of age (U-15) participated in this study. Each player performed a sprinting test (10 m and 30 m sprints) and played a SG on two different pitch sizes (small at 100 [SSG] and large at 200 [LSG] m² per player). Higher external responses (p < 0.01, ES = ?6.41–1.22) were found in LSG in comparison to SSG, except to distance accelerating and decelerating (p > 0.05, ES = ?0.26–0.27). Players who were faster over 10 and 30 m covered higher distances cruising and sprinting (r = ?0.47/-0.66; ± 0.23/± 0.30, respectively, p < 0.05), performed a greater number of sprints, achieved higher maximum velocity (Vel_max) during LSG and covered a greater distance at high-intensity accelerating (r = ?0.50/-0.70; ±0.21/±0.29, respectively, p < 0.05) during both SG. LSG demanded a higher external load in comparison with SSG. In addition, the improved sprint capacity could allow players to perform greater running activities and short-term actions at high-intensities during SG.     

Association between coping skills,past injury and hip pain and function in adolescent elite female ballet dancers

Objectives: The purpose of this study was to investigate the relationship between coping skills and current hip pain and function scores in ballet dancers. Secondly, we examined the relationship between coping skills and past injuries. Thirdly, we investigated the association between past injuries and current pain and function scores.

Methods: This was a cross-sectional observational study. Twenty-six young elite female dancers (mean age 15.9 years, range 14–17 years) participated. Participants completed surveys indicating past injury history, rating pain and function on the short International Hip Outcome Tool (iHOT-12), and assessing coping skills on the Athletic Coping Skills Inventory Score (ACSI-28). Independent t-tests, Cohen’s d, effect size, chi-square and correlation coefficient and determination analyses were conducted.

Results: There was no significant relationship between iHOT-12 scores and ACSI-28 scores (r = ?0.250, p = 0.087). There was no significant difference (p = 0.289) in past injuries comparing those with ACSI-28 scores above and below the mean ACSI-28. A significant moderate negative correlation was detected between both iHOT-12 scores and total past injuries (r = ?0.609, p < 0.001), and iHOT-12 scores and past non-hip injuries (r = ?0.628, p < 0.001).

Conclusion: Past injuries may influence current hip pain and function in young female dancers. Correlation determination (r²) indicated that 37% of current pain and function scores were explained by total past injuries in a small group of young high-level ballet dancers. Further research should engage a prospective design to investigate the predictive ability of findings.     

Comparison of baseline and post-concussion ImPACT test scores in young athletes with stimulant-treated and untreated ADHD

Objectives: Baseline and post-concussion neurocognitive testing is useful in managing concussed athletes. Attention deficit hyperactivity disorder (ADHD) and stimulant medications are recognized as potential modifiers of performance on neurocognitive testing by the Concussion in Sport Group. Our goal was to assess whether individuals with ADHD perform differently on post-concussion testing and if this difference is related to the use of stimulants.

Methods: Retrospective case-control study in which 4373 athletes underwent baseline and post-concussion testing using the ImPACT battery. 277 athletes self-reported a history of ADHD, of which, 206 reported no stimulant treatment and 69 reported stimulant treatment. Each group was matched with participants reporting no history of ADHD or stimulant use on several biopsychosocial characteristics. Non-parametric tests were used to assess ImPACT composite score differences between groups.

Results: Participants with ADHD had worse verbal memory, visual memory, visual motor speed, and reaction time scores than matched controls at baseline and post-concussion, all with p ≤ .001 and |r|≥ 0.100. Athletes without stimulant treatment had lower verbal memory, visual memory, visual motor speed, and reaction time scores than controls at baseline (p ≤ 0.01, |r|≥ 0.100 [except verbal memory, r = ?0.088]) and post-concussion (p = 0.000, |r|> 0.100). Athletes with stimulant treatment had lower verbal memory (Baseline: p = 0.047, r = ?0.108; Post-concussion: p = 0.023, r = ?0.124) and visual memory scores (Baseline: p = 0.013, r = ?0.134; Post-concussion: p = 0.003, r = ?0.162) but equivalent visual motor speed and reaction time scores versus controls at baseline and post-concussion.

Conclusions: ADHD-specific baseline and post-concussion neuropsychological profiles, as well as stimulant medication status, may need to be considered when interpreting ImPACT test results. Further investigation into the effects of ADHD and stimulant use on recovery from sport-related concussion (SRC) is warranted.     

Interrelationships between changes in erythropoietin,plasma volume,haemoglobin concentration,and total haemoglobin mass in endurance athletes

Interrelationships between physiological changes (Δ) in erythropoietin (EPO), plasma volume (PV), haemoglobin concentration ([Hb]), and total haemoglobin mass (tHb-mass) were examined in cyclists who trained in different altitudes. Regardless of differences in pattern of changes observed in three training locations, ΔEPO was correlated positively with ΔPV, negatively with Δ[Hb], and trivially with ΔtHb-mass. Δ[Hb] was negatively correlated with ΔPV. In the pooled data the Spearman’s rank correlation coefficients were as follows: r = 0.783, P < 0.001; r = ?0.704, P < 0.001; r = 0.136, P > 0.05; r = ?0.813, P < 0.001, respectively. The obtained results have shown that EPO does not only regulate [Hb] by erythropoiesis stimulation but also by PV modulation, which probably aims at keeping proper level of arterial oxygen content for oxygen delivery to tissues.     

Optimal load for the muscle power profile of prone bench pull in Brazilian Jiu-Jitsu athletes

Background

No studies were observed optimal intensity loads for the muscle power performance during prone bench pull exercise in Brazilian Jiu-Jitsu athletes (BJJ) and this exercise is more similar with grip technics.

Purpose

To identify the optimal intensity for the muscle power performance variables during PBP exercise in BJJ athletes.

Methods

Fifteen athletes (25.5 ± 4.9 years; 65.6 ± 12.2 kg; 177.5 ± 4.7 cm) performed PBP at 30, 40, 50 and 60% of one repetition maximum (1RM) in a random order. The mean power (MP), mean velocity (MV), mean propulsive power (MPP) and mean propulsive velocity (MPV) were determined by measuring the barbell displacement by a linear encoder.

Results

In all power performance variables, higher power output was observed at 40 and 50% 1RM when compared to 30 and 60% 1RM (MP: F = 29.07; p < 0.001; MV: F = 40.80; p < 0.001; MPP: F = 53.69; p = 0.003; MPV: F = 166.2; p > 0.001). Additionally, it was observed higher MPP at 50% 1RM when compared to 40% 1RM (F = 55.23; p < 0.001). The polynomial adjustment indicated that the optimal intensity load for producing highest power performance ranged from 45 to 50% 1RM (R ² = 0.938–0.989) across all variables.

Conclusion

The loads between 45 and 50% 1RM produced the optimal muscle power performance during PBP exercise in BJJ athletes.

     

Injuries observed in a prospective transition from traditional to minimalist footwear: correlation of high impact transient forces and lower injury severity

Objectives: Minimalist running is increasing in popularity based upon a concept that it can reduce impact forces and decrease injury rates. The purpose of this investigation is to identify the rate and severity of injuries in runners transitioning from traditional to minimalist footwear. The secondary aims were to identify factors correlated with injuries.

Methods: Fourteen habitually shod (traditional running shoes) participants were enrolled for this prospective study investigating injury prevalence during transition from traditional running shoes to 5-toed minimalist shoes. Participants were uninjured, aged between 22-41 years, and ran at least twenty kilometers per week in traditional running shoes. Participants were given industry recommended guidelines for transition to minimalist footwear and fit with a 5-toed minimalist running shoe. They completed weekly logs for identification of injury, pain using Visual Analogue Scale (VAS), injury location, and severity. Foot strike pattern and impact forces were collected using 3D motion analysis at baseline, 4 weeks, and 12 weeks. Injuries were scored according to a modified Running Injury Severity Score (RISS).

Results: Fourteen runners completed weekly training and injury logs over an average of 30 weeks. Twelve of 14 (86%) runners sustained injuries. Average injury onset was 6 weeks (range 1–27 weeks). Average weekly mileage of 23.9 miles/week prior to transition declined to 18.3 miles/week after the transition. The magnitude of the baseline impact transient peak in traditional shoes and in minimalist shoes negatively correlated with RISS scores (r = ?0.45, p = 0.055 and r = ?0.53, p = 0.026, respectively).

Conclusion: High injury rates occurred during the transition from traditional to minimalist footwear. Non-compliance to transition guidelines and high injury rates suggest the need for improved education. High impact transient forces unexpectedly predicted lower modified RISS scores in this population.     

The relationship between brain-derived neurotrophic factor,irisin and cognitive skills of endurance athletes

Objective: The objective of this study was to assess the cognitive performance of endurance athletes and its relation with circulating brain-derived neurotrophic factor (BDNF) and irisin levels.

Methods: 26 endurance athletes (14 elite orienteers (mean ± SD: age = 26.33 ± 4.08, body weight = 70.33 ± 4.64, body height = 177.7 ± 6.1), 12 pentathletes (mean ± SD: age = 29.42 ± 5.32, body weight = 74.77 ± 6.59, body height = 180.8 ± 3.8)) and ten sedentary (mean ± SD: age = 27.30 ± 2.06, body weight = 76.65 ± 12.50, body height = 176.9 ± 5.2) men at almost same ages and educational levels participated in this study. Cognitive functions were analyzed with mini-mental-state examination (MMSE) and Isaacs’ Set Test of Verbal Fluency (IST) tests. Insulin-like growth factor-1 (IGF-1), BDNF and irisin levels were measured in the blood samples.

Results: The MSSE and IST scores of the endurance athletes were higher than that of the sedentary control group (P < 0.05). Serum IGF-1 levels were higher in the pentathletes (111.18 ± 22.26 ng mL^?1) than the orienteers (85.89 ± 19.32 ng mL^?1) (P < 0.05). Plasma BDNF (2.78 ± 0.81, 4.28 ± 1.03, and 3.93 ± 0.77 ng mL^?1 in the sedentary, orienteers and pentathletes, respectively) and irisin (3.25 ± 0.70, 6.16 ± 0.99, and 6.58 ± 1.09 µg mL^?1 in the sedentary, orienteers and pentathletes, respectively) concentrations of the endurance trained athletes were higher than that of the sedentary control group (P < 0.05). Positive correlation between the cognitive function test results and BDNF and irisin concentrations were observed (P < 0.05). There was also a positive correlation between the circulating irisin and BDNF concentrations (P < 0.05).

Conclusion: These results suggested that irisin and BDNF levels positively correlated with cognition in the endurance trained athletes.     

Relation between peak knee flexion angle and knee ankle kinetics in single-leg jump landing from running: a pilot study on male handball players to prevent ACL injury

Objectives: The relationship between knee kinematics and knee-ankle kinetics during the landing phase of single leg jumping has been widely studied to identify proper strategies for preventing non-contact ACL injury. However, there is a lack of study on knee-ankle kinetics at peak knee flexion angle during jumping from running. Hence, the purpose of this study is to establish the relationship between peak knee flexion angle, knee extension moment, ankle plantar flexion moment and ground reaction force in handball players in order to protect ACL from excessive stress during single leg jumping. In addition, the study also clarifies the role of calf muscles in relieving part of ACL stresses with different knee flexion angles during landing.

Methods: Fifteen active male elite handball players of Saudi Arabia have participated in this study (Age = 22.6 ± 3.5years, Height = 182 ± 3.7 cm, Weight = 87.5 ± 10.2 kg). The players performed three successful landings of single-leg jump following running a fixed distance of about 450cm. The data were collected using a 3D motion capture and analysis system (VICON).

Results: Pearson product moment correlation coefficients showed that greater peak knee flexion angle is related significantly to both lesser knee extension moment (r = -.623, P = .013) and vertical component of ground reaction force (VGRF) (r = -.688, P = .005) in landing phase. Moreover, increasing the peak knee flexion angle in landing phase tends to increase the ankle plantar flexion moment significantly (r = .832, P = .000).

Conclusion: With an increase of the peak knee flexion angle during single leg jump landing from running, there would be less knee extension moment, low impact force and more plantar flexion moment. As such, the clinical implication of this study is that there may be a possible protective mechanism by increasing the knee flexion angle during landing phase, which tends to protect the ACL from vigorous strain and injuries.     

Order effects of high-intensity intermittent and strength exercise on lipoprotein profile

Purpose

To compare the effects of the order of concurrent exercise (endurance plus strength or strength plus endurance) on lipoprotein profiles in men.

Methods

After the evaluation of maximum strength (one repetition maximum—1RM) in the half-squat and of aerobic fitness (maximal velocity in treadmill incremental test), 11 physically active male subjects underwent two randomized sessions composed of four sets of half-squat strength exercises until exhaustion (at 80 % of 1RM) and a 5-km run high-intensity intermittent exercise (1:1 min at V _max), performed in different orders: (1) strength plus run (S-A) and inverse order, and run plus strength (A-S). Blood samples were collected before and immediately after the first exercise (Post-1) and after the second exercise (Post-2) in the intra-session sequence. Serum was analyzed for total cholesterol (TC) and its ratio, HDL-c and LDL-c, and triacylglycerol (TAG).

Results

There were effects of condition for TC, LDL-c, and TC/HDL, with greater values in the AS than SA (p < 0.001 for all). For the delta analysis, there was an interaction effect for TAG, with greater delta-1 S-A than delta-1 A-S (p = 0.035), and higher delta-1 S-A than delta-2 S-A (p = 0.001); for LDL-c, with higher delta-1 S-A values than delta-2 S-A (p = 0.010); and for TC, with higher delta-1 S-A values than delta-2 S-A (p = 0.038).

Conclusion

We conclude that there are no differences between the order of acute high-intensity intermittent run plus strength exercises regarding modulation of the lipoprotein profile in healthy, physically active men.

     

Effect of ballistic and power training on performance adaptations of élite table tennis players

The purpose of this study was to examine the effects of ballistic and power training on the skills, physical fitness and body composition adaptations of élite table tennis players. Thirty male table tennis players (age: 24?±?7 years, stature: 175?±?6 cm, body mass 74?±?16 kg, percentage of fat mass (%FM) 12?±?7%, mean?±?SD), who were able to perform top spin strike properly, were randomly assigned to three groups: power training (PT), ballistic training (BT) and no training (Control, CON). PT and BT trained 3 times per week for 8 weeks. PT consisted of three sets for six different stations, 60–80% of one repetition maximum (1RM). BT consisted of three sets for five different throwing exercises. Pre- and post-intervention group comparisons were analyzed using a two-way ANOVA with repeated measurements of two factors (group?×?time). After training, significant interactions were observed in increasing muscle strength, muscle endurance, explosive power, anaerobic power, agility and grip strength regardless of the exercise methods (p?<?0.05). Moreover, both training regimens were not effective in changing body composition, reaction time and skills (p?>?0.05). In conclusion, the results of the present study suggest that physical fitness adaptations can be increased similarly after 8 weeks of power and ballistic training, in table tennis players. So coaches and elite table tennis players can use ballistic and power training to improve their performance without having to worry about the negative impact of their training on their skill and explosive power performance.

     

Acute effects of static stretching on passive stiffness and postural balance in healthy,elderly men

Objectives: This study aimed to examine the acute effects of straight-leg raise (SLR) static stretching on passive stiffness and postural balance in healthy, elderly men. An additional aim of this study was to examine the relationships between stiffness and balance at baseline (prior to stretching) and the relationships between the stretch-induced changes in these variables.

Methods: Eleven elderly men (age = 69 ± 6 years; height = 177 ± 7 cm; mass = 83 ± 13 kg) underwent postural balance and passive stiffness assessments before and after: 1) a stretching treatment consisting of four, 15-s SLR static stretches performed by the primary investigator and 2) a control treatment consisting of no static stretching. Passive stiffness was calculated from the slopes of the initial (phase 1) and final (phase 2) portions of the angle–torque curve. Unilateral postural balance was assessed on the right leg using a commercially designed balance testing device, which provides a measurement of static stability based on the overall stability index (OSI).

Results: The slope coefficients and OSI values decreased from pre- to post-treatment for the stretching intervention (P = 0.015 and 0.018, respectively); however, there were no changes for the control (P = 0.654 and 0.920). For the stretching intervention, a significant positive relationship was observed between OSI and the slope coefficient of phase 1 at baseline (r = 0.619; P = 0.042). A significant positive relationship was also observed between the stretched-induced changes in OSI and the slope coefficient of phase 1 (r = 0.731; P = 0.011). No relationship was observed between OSI and the slope coefficient of phase 2 at baseline (r = 0.262; P = 0.437) nor was there a relationship between the changes in these variables (r = 0.419; P = 0.200).

Conclusion: A short, practical bout of SLR static stretching may be an effective intervention for reducing passive stiffness and improving postural balance in healthy, elderly men.     

Effect of maximum grip strength on controlled force exertion measured by a computer-generated sinusoidal waveform in young adult males

Context

It is important to develop a method to accurately measure controlled force exertion (CFE).

Objectives

This study aimed to examine the effect of maximum grip strength on CFE measured by a sinusoidal waveform in 81 right-handed young males aged 15–29 years.

Methods

On the basis of grip strength measurements, participants were divided into the following three groups: low (males 20; mean age 19.5 years; standard deviation (SD) = 5.0 years), medium (males 41; mean age 22.8 years; SD = 4.2 years), and high (males 20; mean age 23.7 years; SD = 3.4 years). Participants adjusted the submaximal grip strength of the dominant hand with changes in the demand values that were displayed as a sinusoidal waveform with a frequency of 0.1 Hz on a computer screen. The abovementioned test was performed three times with a 1-min interval after one practice trial. Each trial lasted 40 s. The sum of the differences between the demand value and grip exertion strength value for 25 s was considered as the evaluation parameter.

Results

Controlled force exertion values demonstrated insignificant correlations with age and maximum grip strength in all groups (r = 0.07; r = ?0.12; p > 0.05). No significant differences were found between CFE mean scores that was adjusted for age and varying maximum grip strength in the three groups (F = 1.95; p > 0.05).

Conclusions

Based on the sinusoidal waveform display, we inferred that maximum grip strength has little effect on CFE evaluation in young males.     

Effect of physical activity on levels of homocysteine,folate, and vitamin B12 in the elderly

Objectives: Homocysteine (Hcy) has emerged as a risk factor for cardiovascular diseases (CVD). However the relationship of physical activity (PA) with Hcy levels in the elderly is controversial. Accordingly, the current study examined the effect of low and high participation in PA on serum Hcy in young (n = 77; 18–50 years) and old (n = 207; > 65 years) males (n = 141) and females (n = 142). Methods: Level of PA was obtained in a 1-to-1 interview and participants divided into low and high groups. Serum Hcy, folate, and vitamin B₁₂ were obtained after 12 hour fast drawn by venipuncture. Results: Levels of Hcy correlated with folate (r = ?0. 5; p = 0.000) and vitamin B₁₂ (r = ?0.3; p = 0.000). The ANOVA revealed a main effect of PA for Hcy (p = 0.04) but not for folate (p = 0.2) and vitamin B₁₂ (p = 0.2). Main effects were found also of age for Hcy (p = 0.000) and folate (p = 0.005) as well as of gender for Hcy (p = 0.000) and vitamin B₁₂ (p = 0.000). Subsequent ANCOVA showed lower levels of Hcy in the participants with greater versus lower PA even after controlling for B₁₂ vitamin. Conclusion: These results confirm the importance of the vitamins for regulating Hcy levels. Additionally, the data suggests that PA affects Hcy levels without affecting and independent of B vitamins in the elderly.     

Multimodal approach towards understanding the changes in the autonomic nervous system induced by an ultramarathon

ABSTRACT

Purpose: Running an ultramarathon can be considered as a multifaceted, intense stressor inducing changes within the autonomic nervous system (ANS). The aim of this study was to examine changes within and across ANS modalities in response to an ultramarathon.

Methods: Thirteen runners (44.3 ± 5.9 years) completed a 65 km run. Electrodermal activity (EDA), heart rate (HR), and skin temperature measured at wrist (Temp), were recorded before and after running. Three-minute intervals were analysed. Mean values were compared by t-tests for dependent samples. Joint principal component analysis-canonical correlation analysis (PCA-CCA) and multiset CCA techniques were employed to measure the interactions between either any two or among all modalities.

Results: HR (p < 0.01) and EDA (p < 0.01) increased, while Temp decreased (p < 0.01). PCA-CCA revealed one significant component (p < 0.05) for each modality pair in pre and post measures. Component strength increased from pre (mean = 0.73) to post (mean = 0.92) test. Multiset CCA supported the assumption of increasing strength of correlations across modalities.

Conclusion: Ultramarathon, an intense physical stressor, increases correlations across modalities pointing towards a reorganization of central ANS control to restore dynamic balance after physical load. This characterization of ANS-states might offer new avenues for training control.     

Weight status and physical fitness in female soccer players: is there an optimal BMI?

The aim of this study was to examine the relationship between weight status and physical fitness in female soccer players. For this purpose, 54 soccer players [21.7 (4.0) years, 60.5 (7.0) kg, 164.3 (4.7) cm, mean (standard deviation)] underwent a physical fitness battery. To study this relationship we used a correlation analysis and compared three groups differing in body mass index (BMI): group A (BMI < 21 kg m^?2), B (21 < BMI < 23 kg m^?2) and C (BMI > 23 kg m^?2). We found very large correlations between BMI and the components of somatotype (0.70 ≤ |r| ≤ 0.92, p < 0.001). BMI was also correlated with isometric muscle strength and leg muscle power (W) assessed by the Wingate anaerobic test (WAnT) and force–velocity test. In contrast, when muscle power was expressed as W kg^?1, the correlation was negative. We also found an inverse relationship between BMI and fatigue index of WAnT (r = 0.36, p < 0.05): the higher the BMI, the higher was the decrease in performance during this 30 s all-out test. The comparison between A, B and C groups revealed differences in the same direction as the correlation analysis. We concluded that weight status is closely related with body composition, somatotype and leg muscle power. Therefore, achieving an optimal BMI might result in improvements with regard to physique and anaerobic power, and consequently in performance enhancement.     

The effects of nutrient timing on training adaptations in resistance-trained females

Objectives

The purpose of this study was to determine the effects of pre- vs. post-workout nutrition on strength, body composition, and metabolism in trained females over 6 weeks of high intensity resistance training (HIRT).

Effect of acute exercise-induced fatigue on maximal rate of heart rate increase during submaximal cycling

Different mathematical models were used to evaluate if the maximal rate of heart rate (HR) increase (rHRI) was related to reductions in exercise performance resulting from acute fatigue. Fourteen triathletes completed testing before and after a 2-h run. rHRI was assessed during 5 min of 100-W cycling and a sigmoidal (rHRI_sig) and exponential (rHRI_exp) model were applied. Exercise performance was assessed using a 5-min cycling time-trial. The run elicited reductions in time-trial performance (1.34 ± 0.19 to 1.25 ± 0.18 kJ · kg^?1, P < 0.001), rHRI_sig (2.25 ± 1.0 to 1.14 ± 0.7 beats · min^?1 · s^?1, P < 0.001) and rHRI_exp (3.79 ± 2.07 to 1.98 ± 1.05 beats · min^?1 · s^?1, P = 0.001), and increased pre-exercise HR (73.0 ± 8.4 to 90.5 ± 11.4 beats · min^?1, P < 0.001). Pre-post run difference in time-trial performance was related to difference in rHRI_sig (r = 0.58, P = 0.04 and r = 0.75, P = 0.003) but not rHRI_exp (r = ?0.04, P = 0.9 and r = 0.27, P = 0.4) when controlling for differences in pre-exercise and steady-state HR. rHRI_sig was reduced following acute exercise-induced fatigue, and correlated with difference in performance.