The Energy Expenditure Associated With Body-Weight Resistance Exercises of Various Movement Patterns Performed at Different Durations

ABSTRACT

Poulios, A, Fotiou, C, Draganidis, D, Avloniti, A, Rosvoglou, A, Batrakoulis, A, Tsimeas, P, Papanikolaou, K, Deli, CK, Stampoulis, T, Douroudos, II, Chatzinikolaou, A, Jamurtas, AZ, and Fatouros, IG. The energy expenditure associated with body-weight resistance exercises of various movement patterns performed at different durations. J Strength Cond Res XX(X): 000-000, 2024-Although body-weight resistance exercises (BWRE) are popular and effective for body mass reduction and neuromuscular performance, limited information exists regarding their total energy expenditure (TEE). This study determined the energy cost associated with seven BWRE of different movement patterns plank, push-ups, squat, single-leg squat [SLS], forward lunge [FL], burpees, and jumping jacks [JJ] using 2 different durations (T30: 30-second; T45: 45-second) in 10 healthy young adults using a randomized, 2-trial, crossover, repeated-measures design. The level of significance was set at p ≤ 0.05. The burpees were associated with the highest and the plank with the lowest intensity (rates of perceived exertion [RPE] and mean heart rate [MHR]) and metabolic load (blood lactate [BL] accumulation, metabolic equivalents of task [METs], and excess post-exercise oxygen consumption [EPOC]) in both trials. In T30 and T45, TEE (kcals per minute) was 11.3/12.6 in plank, 18.6/22.0 in FL, 19.8/21.2 in SLS, 19.9/23.2 in squat, 22.0/24.9 in push-ups, 23.1/22.8 in JJ, and 32.2/40.7 in burpees. Although RPE, MHR, BL, and EPOC were comparable among T30 and T45, METs and TEE were greater in T45. These results suggest that TEE of BWRE ranges from ∼11 to 40 kcals·min-1, depending on the movement pattern and the duration of exercise. This information may be valuable for those using BWRE for body-weight management and improvement of strength performance.

Using Bar Velocity to Assess Post-match Neuromuscular Fatigue in Young Soccer Players

This study aimed to investigate the recovery of neuromuscular performance using mechanical parameters collected during jump (vertical and horizontal) and strength-power exercises in youth soccer players after official soccer matches. Twenty-one outfield highly trained youth male soccer athletes (age: 18.23±0.73 years; weight: 72.12±6.99 kg; height: 1.78±0.08 m) from two teams competing in the 1st division of U-19 Portuguese National Championship participated in this study. Players completed a battery of physical tests at -2 h, + 30 min, +24 h, and +48 h in relation to the match. Countermovement jump height, horizontal jump distance, and bar velocity during the half squat, bench press, and hip thrust exercises, at fixed loads, were recorded. Countermovement jump was impaired until 24 h post-match (-: 1.7% from pre- to 24 h post-match, p=0.050; ES=-: 0.82). Half-squat bar velocity was reduced immediately following the match (-: 6.8% from pre-match, p=0.004; ES=-: 0.64) but recovered at +24 h (+2.9%, p=1.00; ES=0.02). Hip-thrust bar velocity was reduced for up to 48 h post-match (-: 7.4% from pre- to 48 h post-match, p<0.001; ES=-: 0.80). No impairments were found in the horizontal jump and bench press at any moment. Our findings show prolonged decrements in strength of the posterior chain following a soccer match, measured in the hip thrust exercise, while the other exercises displayed faster recovery dynamics.

Electric Muscle Stimulation (EMS) Does Not Improve Anaerobic Performance Measures During a Repeated Wingate Test

Introduction: The aim of this study was to examine differences between a control warm-up and an Electric Muscle Stimulation (EMS)-induced warm-up in off-road cyclists when examining anaerobic performance measures from a repeated Wingate test (WAnT). Methods: Twelve trained off-road cyclists completed a randomized crossover study (age: 31 ± 10 years, height: 176.79 ± 6.09 cm, body mass: 74.57 ± 4.77 kg). Participants completed two randomized, separate testing sessions involving a control warm-up and an EMS warm-up before undergoing the repeated WAnT, which was used to collect anaerobic performance and physiolo- gical measures during both sessions. High-frequency EMS was applied to the knee extensor muscles for 4 min after a standardized warm-up during the EMS session. Results: Analysis revealed that there were no significant differences between mean power output, peak power output, and percentage decrement between the two sessions. The EMS session resulted in significantly lower average HR values and significantly lower differences in pre-to-post-test blood lactate values when compared to the control session. Discussion: According to the results of this study, an acute application of EMS is not a useful tool for off-road cyclists to improve power output or maintain anaerobic capacity. Hence, its use before competition is questionable.

Time Course of Performance Indexes, Oxidative Stress, Inflammation, and Muscle Damage Markers after a Female Futsal Match

BACKGROUND

Our aims were to investigate the time-course effects of a futsal match on performance, oxidative stress, and muscle damage markers, as well as inflammatory and antioxidant responses during a 6-day post-match period.

METHODS

Thirty-four female high-level futsal players were assessed on several oxidative stress, inflammation, subjective muscle soreness, subjective rate perceived exertion, and performance tests before a futsal match, immediately after, and 24 h to 144 h after.

RESULTS

Counter movement jump, 20 m, and 10 m sprints performance significantly decreased immediately after the match (p < 0.05) and returned to baseline 72 h post-match (p > 0.05). Delayed onset muscle soreness peaked 24 h post-match and rate perceived exertion peaked post-match (p < 0.05) and returned to baseline 96 h post-match (p > 0.05). Inflammatory biomarkers peaked at 24 h (p < 0.05) and remained significantly elevated for 72 h after the match (p < 0.05). Muscle damage biomarkers peaked at 24 h (p < 0.05) and remained significantly (p < 0.05) elevated for at least 72 h after the match. Oxidative stress markers peaked at 24 h-48 h (p < 0.05) and returned to baseline 120 h post-match (p > 0.05). In respect to antioxidant responses, these peaked at 24 h-48 h post-match (p < 0.05) and returned to baseline 120 h after the match (p > 0.05).

CONCLUSIONS

A single futsal match induces short/mid-term changes in performance, inflammation, oxidative stress, and muscle damage markers for about 72 h-96 h post-match.

Comparison between Match and Training Session on Biomarker Responses in Handball Players

A variety of loads are placed upon an athlete in team sports (e.g., training, match, or competitions). However, the volume of the training load plays an important role in match success. Therefore, the aim of this study was to compare the differences in biomarker dynamics during the match and during training, and to evaluate if such training represents a good stimulus for an athlete to adapt to match stress. Ten male handball players (average age of 24.1 ± 3.17 years, body height of 1.88 ± 0.64 m, and body mass of 94.6 ± 9.6 kg) took part in this study. Their saliva cortisol, testosterone, and alpha-amylase were sampled during the match and training (sessions of 90 min duration, respectively). The results showed that cortisol had higher values after the match (0.65 µg/dL) than after training (0.32 µg/dL) (p = 0.05; ES = 0.39). Testosterone concentrations had a steeper increase during a match (65%) than after training (37%). Alpha-amylase levels did not differ significantly between the match and training (p = 0.77; ES = -0.06). Overall, the results showed that the environment of a match was more stressful for the athletes; therefore, a match provoked a stronger endocrine response in the studied markers. Therefore, we concluded that a match seemed to be a stronger trigger for all of the measured biomarker responses.

Spirulina supplementation prevents exercise-induced lipid peroxidation, inflammation and skeletal muscle damage in elite rugby players

BACKGROUND

The present study aimed to examine the effects of spirulina supplementation on pro/antioxidant status, inflammation and skeletal muscle damage markers immediately and 24 h after exhaustive exercise in elite rugby players.

METHODS

Seventeen elite male Rugby Union players were randomly assigned to a spirulina (SPI: n = 9) or placebo (PLA: n = 8) group in a double-blind design. Subjects were supplemented with Spirulina platensis (5.7 g day^-1 ) or placebo (isoproteic and caloric) for 7 weeks. At baseline and after 7 weeks of supplementation, blood samples were obtained before (T0), immediately after (T1) and 24 h after (T2) exhaustive exercise. The Yoyo Intermittent Recovery Test Level 2 was used as an exhaustive exercise to induce oxidative stress (OS), inflammation and skeletal muscle damage. The studied parameters included pro/antioxidant status markers (superoxide dismutase, glutathione peroxidase, reduced glutathione/glutathione disulphide ratio, oxidised low-density lipoprotein and F2α-isoprostanes [F2-Isop]), inflammation markers (myeloperoxidase and C-reactive protein [CRP]) and skeletal muscle damage markers (lactate dehydrogenase and creatine kinase [CK]).

RESULTS

Our results showed that F2-Isop, CRP and CK levels significantly increased at T1 only in the PLA group (p < 0.05, p < 0.05 and p < 0.001, respectively) with no change in the SPI group, which reflects the effect of spirulina to prevent lipid peroxidation, inflammation and skeletal muscle damage induced by exhaustive exercise. Moreover, spirulina supplementation accelerated the return to baseline values given that F2-Isop, CRP and CK levels at T2 were significantly lower than at T0 in the SPI group (p < 0.05, p < 0.01 and p < 0.001, respectively).

CONCLUSIONS

Based on the markers used in the present study, our results show that spirulina supplementation potentially prevents exercise-induced lipid peroxidation, inflammation and skeletal muscle damage, and may also accelerate the recovery of some of these markers. Based on our findings, we recommend spirulina supplementation especially for those athletes who do not achieve the recommended antioxidant dietary intake and who perform a high training load aiming to reduce the magnitude of OS, inflammation and skeletal muscle damage, which could help to reduce performance losses and accelerate recovery after training/competitions throughout the season.

Comparison between Eccentric-Only and Coupled Concentric-Eccentric Contractions for Neuromuscular Fatigue and Muscle Damage

PURPOSE

Eccentric contractions induce muscle damage, but less is known about the effects of preceding concentric contractions to eccentric contractions on muscle damage. We compared eccentric-only (ECC) and coupled concentric and eccentric contractions (CON-ECC) of the knee extensors for parameters of neuromuscular fatigue and muscle damage.

METHODS

Twenty participants (age, 19-36 yr) were randomly placed into an ECC or a CON-ECC group (n = 10 per group), without significant (P > 0.06) differences in baseline neuromuscular variables between groups. The ECC group performed six sets of eight ECC at 80% of ECC one-repetition maximum (1-RMecc), whereas the CON-ECC group performed six sets of eight alternating concentric (CON) and ECC (16 contractions per set) at 80% of CON 1-RM and 1-RMecc, respectively. Maximal voluntary isometric contraction force, rate of force development, resting twitch force, maximal M-wave (MMAX), voluntary activation, motor evoked potentials, corticospinal silent period, short interval intracortical inhibition, and muscle soreness were measured before, immediately after, and 1-3 d after exercise.

RESULTS

No significant (P ≥ 0.09) differences between ECC and CON-ECC were observed for changes in any variables after exercise. However, maximal voluntary isometric contraction force decreased immediately after exercise (ECC: -20.7% ± 12.8%, CON-ECC: -23.6% ± 23.3%) and was still reduced 3 d after exercise (ECC: -13.6% ± 13.4%, CON-ECC: -3.3% ± 21.2%). Rate of force development at 0-30 ms reduced immediately after exercise (ECC: -38.3% ± 33.9%, CON-ECC: -30.7% ± 38.3%). Voluntary activation, resting twitch force, and motor evoked potential/MMAX decreased and corticospinal silent period increased after exercise (all P ≤ 0.03), but short interval intracortical inhibition and MMAX did not change. Muscle soreness developed (P < 0.001) similarly for both groups (peak, 38.5 ± 29.5 mm).

CONCLUSIONS

CON-ECC did not exacerbate neuromuscular fatigue and muscle damage when compared with ECC, despite twice as many contractions performed. Thus, eccentric contractions (n = 48 in both groups) seemed to mainly mediate the neuromuscular responses observed.

Early Detection of Prolonged Decreases in Maximal Voluntary Contraction Force after Eccentric Exercise of the Knee Extensors

PURPOSE

We examined whether the magnitude of muscle damage indicated by changes in maximal voluntary isometric contraction (MVIC) strength 1 to 3 d after unaccustomed eccentric exercise (ECC) was correlated with changes in central and peripheral neuromuscular parameters immediately post-ECC.

METHODS

Twenty participants (19-36 yr) performed six sets of eight eccentric contractions of the knee extensors. Rate of force development (RFD) during knee extensor MVIC, twitch force, rate of force development (RFDRT) and rate of relaxation (RRRT) of the resting twitch, maximal M-wave (MMAX), voluntary activation, silent period duration, motor-evoked potentials (MEP) and short-interval intracortical inhibition were assessed before, immediately after, and 1 to 3 d post-ECC. Relationships between changes in these variables immediately post-ECC and changes in MVIC strength at 1 to 3 d post-ECC were examined by Pearson product-moment (r) or Spearman correlations.

RESULTS

Maximal voluntary isometric contraction strength decreased (-22.2% ± 18.4%) immediately postexercise, and remained below baseline at 1 (-16.3% ± 15.2%), 2 (-14.7% ± 13.2%) and 3 d post-ECC (-8.6% ± 15.7%). Immediately post-ECC, RFD (0-30-ms: -38.3% ± 31.4%), twitch force (-45.9% ± 22.4%), RFDRT (-32.5% ± 40.7%), RRRT (-38.0% ± 39.7%), voluntary activation (-21.4% ± 16.5%) and MEP/MMAX at rest (-42.5% ± 23.3%) also decreased, whereas the silent period duration at 10%-MVIC increased by 26.0% ± 12.2% (P < 0.05). Decreases in RFD at 0 to 30 ms, 0 to 50 ms, and 0 to 100 ms immediately post-ECC were correlated (P < 0.05) with changes in MVIC strength at 1 d (r = 0.56-0.60) and 2 d post-ECC (r = 0.53-0.63). Changes in MEP/MMAX at 10%-MVIC immediately post-ECC were correlated with changes in MVIC strength at 1 d (r = -0.53) and 2 d (r = -0.54) post-ECC (P < 0.05).

CONCLUSIONS

The magnitude of decrease in MVIC strength at 1 to 3 d after ECC was associated with the magnitude of changes in RFD and MEP/MMAX immediately post-ECC. However, based on individual data, these markers were not sensitive for the practical detection of muscle damage.

Biochemical Monitoring of Muscle Recovery in Elite Handball Using an Individualized Approach

Purpose: To evaluate the classification performance of a new method to individualize reference ranges for biomarkers of muscle recovery in elite handball. Methods: In a longitudinal observational study, creatine kinase (CK) and urea levels were assessed in 16 male elite handball players during the 2019–20 preseason. Blood samples were collected at prespecified time points when players were considered either recovered or nonrecovered. Initially, linear mixed-effects models were calculated, as outlined in the study design, to examine the effect of recovery status on CK and urea levels. Finally, a fixed-effect model was calculated for urea based on the law of parsimony. Individualized reference ranges were calculated using a recently published algorithm. To investigate whether the individualized approach resulted in a more accurate classification of recovery status (recovered or nonrecovered), it was compared with a group-based approach derived from the same data set, utilizing predefined error rates. Results: Linear mixed-effects models showed a large effect of recovery status on CK (P < .001, d = 3.49) and a small effect on urea (P = .018, d = 0.382). In contrast to CK (P = .017), urea had no significant interindividual variation. Hence, individualization was examined only for CK. The numerical decrease in both CK error rates by the individualized approach was significant for the test-pass error rate (P = .0196, ϕ = .19). Conclusions: Our findings underscore the critical role of CK for monitoring in team sports such as handball. The observed improvement in CK error rates suggests a promising opportunity to individualize biochemical monitoring, although further studies encompassing larger sample sizes are warranted.

Nutritional optimization for female elite football players-topical review

Women's football is an intermittent sport characterized by frequent intense actions throughout the match. The high number of matches with limited recovery time played across a long competitive season underlines the importance of nutritional strategies to meet these large physical demands. In order to maximize sport performance and maintain good health, energy intake must be optimal. However, a considerable proportion of female elite football players does not have sufficient energy intake to match the energy expenditure, resulting in low energy availability that might have detrimental physiologic consequences and impair performance. Carbohydrates appear to be the primary fuel covering the total energy supply during match-play, and female elite football players should aim to consume sufficient carbohydrates to meet the requirements of their training program and to optimize the replenishment of muscle glycogen stores between training bouts and matches. However, several macro- and micronutrients are important for ensuring sufficient energy and nutrients for performance optimization and for overall health status in female elite football players. The inadequacy of macro-and micronutrients in the diet of these athletes may impair performance and training adaptations, and increase the risk of health disorders, compromising the player's professional career. In this topical review, we present knowledge and relevant nutritional recommendations for elite female football players for the benefit of sports nutritionists, dietitians, sports scientists, healthcare specialists, and applied researchers. We focus on dietary intake and cover the most pertinent topics in sports nutrition for the relevant physical demands in female elite football players as follows: energy intake, macronutrient and micronutrient requirements and optimal composition of the everyday diet, nutritional and hydration strategies to optimize performance and recovery, potential ergogenic effects of authorized relevant supplements, and future research considerations.

Effects of Cardiovascular, Resistance and Combined Exercise Training on Cardiovascular, Performance and Blood Redox Parameters in Coronary Artery Disease Patients: An 8-Month Training-Detraining Randomized Intervention

It is well-documented that chronic/regular exercise improves the cardiovascular function, decreases oxidative stress and enhances the antioxidant capacity in coronary artery disease (CAD) patients. However, there is insufficient evidence regarding the chronic effects of different types of training and detraining on cardiovascular function and the levels of oxidative stress and antioxidant status in these patients. Therefore, the present study aimed at investigating the effects of cardiovascular, resistance and combined exercise training followed by a three-month detraining period, on cardiovascular function, physical performance and blood redox status parameters in CAD patients. Sixty coronary artery disease patients were randomly assigned to either a cardiovascular training (CVT, N = 15), resistance training (RT, N = 11), combined cardiovascular and resistance training (CT, N = 16) or a control (C, N = 15) group. The training groups participated in an 8-month supervised training program (training three days/week) followed by a 3-month detraining period, while the control group participated only in measurements. Body composition, blood pressure, performance-related variables (aerobic capacity (VO_2max), muscle strength, flexibility) and blood redox status-related parameters (thiobarbituric acid reactive substances (TBARS), total antioxidant capacity (TAC), reduced glutathione (GSH), oxidized glutathione (GSSG), catalase activity (CAT), protein carbonyls (PC)) were assessed at the beginning of the study, after 4 and 8 months of training as well as following 1, 2 and 3 months of detraining (DT). CVT induced the most remarkable and pronounced alterations in blood pressure (~9% reduction in systolic blood pressure and ~5% in diastolic blood pressure) and redox status since it had a positive effect on all redox-related variables (ranging from 16 to 137%). RT and CT training affected positively some of the assessed (TAC, CAT and PC) redox-related variables. Performance-related variables retained the positive response of the training, whereas most of the redox status parameters, for all training groups, restored near to the pre-exercise values at the end of the DT period. These results indicate that exercise training has a significant effect on redox status of CAD. Three months of detraining is enough to abolish the exercise-induced beneficial effects on redox status, indicating that for a better antioxidant status, exercise must be a lifetime commitment.

Intradialytic Cardiovascular Exercise Training Alters Redox Status, Reduces Inflammation and Improves Physical Performance in Patients with Chronic Kidney Disease

Redox status (RS) perturbations and inflammation are fundamental features of chronic kidney disease (CKD) that are substantially exacerbated in end-stage renal disease (ESRD). This study aimed at investigating the efficacy of a 6-month intradialytic exercise training program on RS, inflammation and physical performance in patients with ESRD. Twenty hemodialysis (HD) patients (17 males, three females) were randomly assigned to either an intradialytic training (bedside cycling) group (TR; n = 10) or a control group (CON; n = 10) for 6 months. Anthropometrics [body mass and height, body mass index (BMI), body composition], physical performance (VO_2peak), functional capacity [North Staffordshire Royal Infirmary (NSRI) walk test, sit-to-stand test (STS-60)], quality of life (short form-36 (SF-36) as well as RS [thiobarbituric acid reactive substances (TBARS), protein carbonyls (PC), reduced (GSH) and oxidized (GSSG) glutathione, GSH/GSSG, total antioxidant capacity (TAC), catalase activity (CAT)] and high-sensitivity C-reactive protein (hs-CRP) were assessed at baseline and after the 6-month intervention. Peak oxygen consumption (VO_2peak) increased by 15% only in TR (p < 0.01). Performance in NSRI, STS-60 and SF-36 improved by 4–13% only in TR (p < 0.01). Exercise training reduced TBARS (by 28%), PC (by 31%) and hs-CRP (by 15%), and elevated GSH (by 52%), GSH/GSSG (by 51%), TAC (by 59%) and CAT (by 15%) (p < 0.01). These findings suggest that engagement in chronic intradialytic cardiovascular exercise alters RS, reduces inflammation and improves performance in patients with ESRD.

Involvement of inflammasome activation via elevation of uric acid level in nociception in a mouse model of muscle pain

Muscle pain is a common condition in many diseases and is induced by muscle overuse. Muscle overuse induces an increase in uric acid, which stimulates the nucleotide-binding oligomerization domain-like receptor (NLR). This receptor contains the pyrin domain NLRP-3 inflammasome which when activated, results in the secretion of potent pro-inflammatory cytokines such as interleukin-1β (IL-1β). The aim of this study was to investigate the involvement of inflammasome activation via the elevation of uric acid level in nociception in a mouse model of muscle pain. The right hind leg muscles of BALB/c mice were stimulated electrically to induce excessive muscle contraction. The left hind leg muscles were not stimulated as a control. Mechanical withdrawal thresholds, levels of uric acid, IL-1β, and NLRP3, caspase-1 activity, and the number of macrophages were investigated. Furthermore, the effects of xanthine oxidase inhibitors, such as Brilliant Blue G, caspase-1 inhibitor, and clodronate liposome, on pain were investigated. In the stimulated muscles, mechanical withdrawal thresholds decreased, and the levels of uric acid, NLRP3, and IL-1β, caspase-1 activity, and the number of macrophages increased compared to that in the non-stimulated muscles. Administration of the inhibitors attenuated hyperalgesia caused by excessive muscle contraction. These results suggested that IL-1β secretion and NLRP3 inflammasome activation in macrophages produced mechanical hyperalgesia by elevating uric acid level, and xanthine oxidase inhibitors may potentially reduce over-exercised muscle pain.

Improving characterization and diagnosis quality of myofascial pain syndrome: a systematic review of the clinical and biomarker overlap with delayed onset muscle soreness

INTRODUCTION

Myofascial pain syndrome (MPS) is one of the most common conditions of chronic musculoskeletal pain, yet its mechanisms are still poorly understood. Delayed Onset Muscle Soreness (DOMS) is also a regional pain syndrome that has clinical similarities to MPS, but has been better investigated. Emerging research suggests that DOMS may be a valid experimental model for studying MPS; however, a comparison of the similarities and differences of these two conditions has previously not been performed. Herein, we aimed to identify the similarities and differences in the clinical features and biomarkers between DOMS and MPS in order to better define MPS and identify future areas of (DOMS-informed) MPS research.

EVIDENCE ACQUISITION

In order to identify similarities and differences in the clinical manifestation and biomarkers of DOMS and MPS, scoping literature searches were performed using Medline (1965-2019), Embase (1966-2019) and Central (1966-2019) databases. Fifty-three full-text articles were reviewed out of the 2836 articles retrieved in the search.

EVIDENCE SYNTHESIS

A scoping review of the literature demonstrated that DOMS and MPS similarly present as conditions of musculoskeletal pain that are associated with decreased strength and limited range of motion. However, while taut bands and discrete tender spots were described in DOMS, none of the studies reviewed have characterized whether these tender points represent the classic myofascial trigger point phenomenon observed in MPS. Certain systemic circulation biomarkers, including inflammatory cytokines and growth factors, were commonly elevated in MPS and DOMS; further research is needed to determine if other biomarkers that are currently characterized in DOMS are useful to enhance the clinical evaluation of MPS.

CONCLUSIONS

DOMS and MPS share clinical and biomarker similarities suggesting that DOMS may be a useful model for studying MPS.

Time Course of Oxidative Stress, Inflammation, and Muscle Damage Markers for 5 Days After a Soccer Match: Effects of Sex and Playing Position

Souglis, A, Bogdanis, GC, Chryssanthopoulos, C, Apostolidis, N, and Geladas, ND. Time course of oxidative stress, inflammation and muscle damage markers for 5 days after a soccer match: Effects of sex and playing position. J Strength Cond Res 32(7): 2045-2054, 2018-This study examined the influence of sex and playing position on the time course of selected oxidative stress, inflammation, and muscle damage markers after an official soccer match. Sixty professional soccer players (30 men and 30 women) were divided into 3 groups, according to their playing position: defenders, midfielders, and attackers. Each group consisted of 10 male and 10 female players. Sixty healthy volunteers (30 men and 30 women) served as control. Blood samples were taken before and after the match and daily for 5 days after the match. Analysis of variance revealed different responses over time between sex and playing positions, as shown by the 3-way interaction, for creatine kinase (CK), protein carbonyls (PCs), catalase, fibrinogen, uric acid (UA), lactate dehydrogenase, reduced glutathione, C-reactive protein, and interleukin 6 (p < 0.01). Male players had higher values compared with women of the same playing position, for all oxidative, inflammatory, and muscle damage indices (p < 0.01). Also, in both sexes, midfielders had higher peaks in all indices compared with defenders (p < 0.05). Five days after the game CK and UA concentrations had not returned to pregame levels in any exercise group, whereas PCs were still elevated in male midfielders and attackers (p < 0.05). These results show that sex and playing position influence the time course of selected oxidative stress, inflammation, and muscle damage markers after an official soccer game. This information should be taken into account by practitioners for the design of training programs after match play.

Variations of perceived load and well-being between normal and congested weeks in elite case study handball team

The aim of this study was two-fold: (i) to analyze the variations in internal load and well-being in professional handball players between normal and congested weeks and (ii) to analyze the variations between training days within weeks. Twenty male players (26.5 ± 4.9 yo) were monitored during a full season. MD-1 (match day -1) revealed larger decreases in muscle soreness (-17.3%, [-26.6;-6.9]) and fatigue (-16.6%, [-24.8;-7.4]) in congested weeks. Regarding MD-2, larger decreases in DOMS (-19.9%, [-30.5;-7.6]), fatigue (-19.7%, [-30.0;-7.9] and the Hooper index (-16.7%, [-25.6;-6.7]) were found in congested weeks. The results of this study reveal that larger variations between normal and congested weeks occurred in MD-2 and MD-3, with greater values of load and lower levels of well-being occurring in normal weeks. Within-weeks changes revealed greater loads occurring on MD-3 and MD-2 in comparison to MD-1; in the opposite way, greater values of muscle soreness and fatigue occurred on MD-1.

Postmatch recovery of physical performance and biochemical markers in team ball sports: a systematic review

Background

Insufficient postmatch recovery in elite players may cause an increased risk of injuries, illnesses and non-functional over-reaching.

Objective

To evaluate postmatch recovery time courses of physical performance and biochemical markers in team ball sport players.

Study design

Systematic review.

Data sources

PubMed and Web of Science.

Eligibility criteria for selecting studies

This systematic review was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The Critical Review Form for Quantitative Studies was used to evaluate quality. Studies were included if they met the following criteria: (1) original research evaluated players’ physical recovery postmatch; (2) team/intermittent sports; and (3) at least two postmeasurements were compared with baseline values.

Results

Twenty-eight studies were eligible. Mean methodological quality was 11.2±1.11. Most used performance tests and biochemical markers were the countermovement jump test, sprint tests and creatine kinase (CK), cortisol (C) and testosterone (T), respectively.

Summary/conclusions

The current evidence demonstrates that underlying mechanisms of muscle recovery are still in progress while performance recovery is already reached. CK recovery time courses are up to ≥72 hours. Soccer and rugby players need more time to recover for sprint performance, CK and C in comparison to other team ball sports. There are more high-quality studies needed regarding recovery in various team sports and recovery strategies on an individual level should be evaluated.

Clinical relevance

Ongoing insufficient recovery can be prevented by the use of the presented recovery time courses as specific practical recovery guidelines.

Protein ingestion preserves proteasome activity during intense aseptic inflammation and facilitates skeletal muscle recovery in humans

The ubiquitin–proteasome system (UPS) is the main cellular proteolytic system responsible for the degradation of normal and abnormal (e.g. oxidised) proteins. Under catabolic conditions characterised by chronic inflammation, the UPS is activated resulting in proteolysis, muscle wasting and impaired muscle function. Milk proteins provide sulphur-containing amino acid and have been proposed to affect muscle inflammation. However, the response of the UPS to aseptic inflammation and protein supplementation is largely unknown. The aim of this study was to investigate how milk protein supplementation affects UPS activity and skeletal muscle function under conditions of aseptic injury induced by intense, eccentric exercise. In a double-blind, cross-over, repeated measures design, eleven men received either placebo (PLA) or milk protein concentrate (PRO, 4×20 g on exercise day and 20 g/d for the following 8 days), following an acute bout of eccentric exercise (twenty sets of fifteen eccentric contractions at 30°/s) on an isokinetic dynamometer. In each trial, muscle biopsies were obtained from the vastus lateralis muscle at baseline, as well as at 2 and 8 d post exercise, whereas blood samples were collected before exercise and at 6 h, 1 d, 2 d and 8 d post exercise. Muscle strength and soreness were assessed before exercise, 6 h post exercise and then daily for 8 consecutive days. PRO preserved chymotrypsin-like activity and attenuated the decrease of strength, facilitating its recovery. PRO also prevented the increase of NF-κB phosphorylation and HSP70 expression throughout recovery. We conclude that milk PRO supplementation following exercise-induced muscle trauma preserves proteasome activity and attenuates strength decline during the pro-inflammatory phase.

Iron Supplementation Effects on Redox Status following Aseptic Skeletal Muscle Trauma in Adults and Children

Exercise-induced skeletal muscle microtrauma is characterized by loss of muscle cell integrity, marked aseptic inflammatory response, and oxidative stress. We examined if iron supplementation would alter redox status after eccentric exercise. In a randomized, double blind crossover study, that was conducted in two cycles, healthy adults (n = 14) and children (n = 11) received daily either 37 mg of elemental iron or placebo for 3 weeks prior to and up to 72 h after an acute eccentric exercise bout. Blood was drawn at baseline, before exercise, and 72 h after exercise for the assessment of iron status, creatine kinase activity (CK), and redox status. Iron supplementation at rest increased iron concentration and transferrin saturation (p < 0.01). In adults, CK activity increased at 72 h after exercise, while no changes occurred in children. Iron supplementation increased TBARS at 72 h after exercise in both adults and children; no changes occurred under placebo condition. Eccentric exercise decreased bilirubin concentration at 72 h in all groups. Iron supplementation can alter redox responses after muscle-damaging exercise in both adults and children. This could be of great importance not only for healthy exercising individuals, but also in clinical conditions which are characterized by skeletal muscle injury and inflammation, yet iron supplementation is crucial for maintaining iron homeostasis. This study was registered at Clinicaltrials.gov Identifier: NCT02374619.

Exercise-Induced Oxidative Stress Responses in the Pediatric Population

Adults demonstrate an upregulation of their pro- and anti-oxidant mechanisms in response to acute exercise while systematic exercise training enhances their antioxidant capacity, thereby leading to a reduced generation of free radicals both at rest and in response to exercise stress. However, less information exists regarding oxidative stress responses and the underlying mechanisms in the pediatric population. Evidence suggests that exercise-induced redox perturbations may be valuable in order to monitor exercise-induced inflammatory responses and as such training overload in children and adolescents as well as monitor optimal growth and development. The purpose of this review was to provide an update on oxidative stress responses to acute and chronic exercise in youth. It has been documented that acute exercise induces age-specific transient alterations in both oxidant and antioxidant markers in children and adolescents. However, these responses seem to be affected by factors such as training phase, training load, fitness level, mode of exercise etc. In relation to chronic adaptation, the role of training on oxidative stress adaptation has not been adequately investigated. The two studies performed so far indicate that children and adolescents exhibit positive adaptations of their antioxidant system, as adults do. More studies are needed in order to shed light on oxidative stress and antioxidant responses, following acute exercise and training adaptations in youth. Available evidence suggests that small amounts of oxidative stress may be necessary for growth whereas the transition to adolescence from childhood may promote maturation of pro- and anti-oxidant mechanisms. Available evidence also suggests that obesity may negatively affect basal and exercise-related antioxidant responses in the peripubertal period during pre- and early-puberty.

Insights into the molecular etiology of exercise-induced inflammation: opportunities for optimizing performance

The study of exercise-induced muscle damage (EIMD) is of paramount importance not only because it affects athletic performance but also because it is an excellent model to study the mechanisms governing muscle cachexia under various clinical conditions. Although, a large number of studies have investigated EIMD and its associated inflammatory response, several aspects of skeletal muscles responses remain unclear. In the first section of this article, the mechanisms of EIMD are reviewed in an attempt to follow the events that result in functional and structural alterations of skeletal muscle. In the second section, the inflammatory response associated with EIMD is presented with emphasis in leukocyte accumulation through mechanisms that are largely coordinated by pro- and anti-inflammatory cytokines released either by injured muscle itself or other cells. The practical applications of EIMD and the subsequent inflammatory response are discussed with respect to athletic performance. Specifically, the mechanisms leading to performance deterioration and development of muscle soreness are discussed. Emphasis is given to the factors affecting individual responses to EIMD and the resulting interindividual variability to this phenomenon.

Inflammaging and Skeletal Muscle: Can Protein Intake Make a Difference?

Inflammaging is the chronic low-grade inflammatory state present in the elderly, characterized by increased systemic concentrations of proinflammatory cytokines. It has been shown that inflammaging increases the risk of pathologic conditions and age-related diseases, and that it also has been associated with increased skeletal muscle wasting, strength loss, and functional impairments. Experimental evidence suggests that the increased concentrations of proinflammatory cytokines and primary tumor necrosis factor α observed in chronic inflammation lead to protein degradation through proteasome activation and reduced skeletal muscle protein synthesis (MPS) via protein kinase B/Akt downregulation. Dairy and soy proteins contain all the essential amino acids, demonstrate sufficient absorption kinetics, and include other bioactive peptides that may offer nutritional benefits, in addition to those of stimulating MPS. Whey protein has antioxidative effects, primarily because of its ability to enhance the availability of reduced glutathione and the activity of the endogenous antioxidative enzyme system. Soy protein and isoflavone-enriched soy protein, meanwhile, may counteract chronic inflammation through regulation of the nuclear transcription factor κB signaling pathway and cytokine production. Although evidence suggests that whey protein, soy protein, and isoflavone-enriched soy proteins may be promising nutritional interventions against the oxidative stress and chronic inflammation present in pathologic conditions and aging (inflammaging), there is a lack of information about the anabolic potential of dietary protein intake and protein supplementation in elderly people with increased systemic inflammation. The antioxidative and anti-inflammatory effects, as well as the anabolic potential of protein supplementation, should be further investigated in the future with well-designed clinical trials focusing on inflammaging and its associated skeletal muscle loss.

Timing of carbohydrate ingestion did not affect inflammatory response and exercise performance during prolonged intermittent running

Background

Carbohydrate ingestion during exercise is known to attenuate exercise-induced elevation of plasma IL-6 concentration. However, the influence of timing of carbohydrate ingestion remains unclear.

Purpose

The present study investigated the influence of different timing of carbohydrate ingestion during a simulated soccer game on exercise performance, metabolic and inflammatory responses.

Methods

Seven active males performed 3 exercise trials in a randomized order. The exercise consisted of two consecutive bouts of 45 min running (4–16 km/h), separated with 15 min rest period between bouts. The subjects ingested carbohydrate gel (1.0 g/kg) immediately before the first bout of exercise (ONE), immediately before first and second bouts of exercise (0.5 g/kg for each ingestion) (TWO) or placebo immediately before exercise (PLA) Time course changes of maximal jump height, peak power output during 6-s maximal pedaling, perceived fatigue and heart rate (HR) were monitored. Blood samples were also drawn to determine blood glucose, serum insulin, free fatty acid (FFA), myoglobin (Mb), creatine kinase (CK) and plasma IL-6 concentrations.

Results

Blood glucose and serum insulin concentrations were significantly higher in the ONE trial after first bout of 45 min exercise compared with PLA trial (P < 0.05), while serum FFA concentration was significantly elevated in PLA compared with ONE and TWO trials after second bout of exercise (P < 0.05). However, changes of jump height, peak power output during 6-s maximal pedaling, perceived fatigue, HR, or indirect muscle damage (Mb, CK) and inflammatory (IL-6) markers were not significantly different among three trials (P > 0.05).

Conclusions

The timing of carbohydrate ingestion did not affect exercise performance, exercise-induced muscle damage or inflammatory response during a simulated soccer game.

The Measurement of Ammonia in Human Breath and its Potential in Clinical Diagnostics

Ammonia is an important component of metabolism and is involved in many physiological processes. During normal physiology, levels of blood ammonia are between 11 and 50 µM. Elevated blood ammonia levels are associated with a variety of pathological conditions such as liver and kidney dysfunction, Reye's syndrome and a variety of inborn errors of metabolism including urea cycle disorders (UCD), organic acidaemias and hyperinsulinism/hyperammonaemia syndrome in which ammonia may reach levels in excess of 1 mM. It is highly neurotoxic and so effective measurement is critical for assessing and monitoring disease severity and treatment. Ammonia is also a potential biomarker in exercise physiology and studies of drug metabolism. Current ammonia testing is based on blood sampling, which is inconvenient and can be subject to significant analytical errors due to the quality of the sample draw, its handling and preparation for analysis. Blood ammonia is in gaseous equilibrium with the lungs. Recent research has demonstrated the potential use of breath ammonia as a non-invasive means of measuring systemic ammonia. This requires measurement of ammonia in real breath samples with associated temperature, humidity and gas characteristics at concentrations between 50 and several thousand parts per billion. This review explores the diagnostic applications of ammonia measurement and the impact that the move from blood to breath analysis could have on how these processes and diseases are studied and managed.

Comparison of inflammatory responses to a soccer match between elite male and female players

The aim of this study was to compare the inflammatory responses between male and female soccer players for a period of 48 hours after an official match. Blood samples were taken from 83 subjects (22 elite male and 21 elite female soccer players and 20 male and 20 female inactive individuals) in the morning of the game day, immediately after the soccer game and 24 and 48 hours after the match. Average relative exercise intensity during the match was similar in male and female players, as indicated by mean heart rate that was 86.9 ± 4.3 and 85.6 ± 2.3% of maximal heart rate (p = 0.23), respectively. Interleukin 6 (IL-6) and tumor necrosis factor alpha (TNF-α) increased 2- to 4-fold above resting values, peaking immediately after the match. C-reactive protein (CRP) and creatine kinase peaked 24 hours after the match. Interleukin 6, CRP, and creatine kinase responses were similar in male and female players, but the peak in TNF-α was 18% higher in male players. Interleukin 6, TNF-α, and CRP at rest were lower in male and female players compared with the control subjects, suggesting a protective effect of regular exercise training regarding the inflammatory profile. The results of this study show that a soccer match induces significant inflammatory responses in both male and female players, with only TNF-α peak values being lower in females. Because of the effects of inflammatory responses on performance and health of the players, it is suggested that coaches and trainers should adjust exercise training programs after a match to promote recovery and protect the athletes' health.

Recovery kinetics of knee flexor and extensor strength after a football match

We examined the temporal changes of isokinetic strength performance of knee flexor (KF) and extensor (KE) strength after a football match. Players were randomly assigned to a control (N = 14, participated only in measurements and practices) or an experimental group (N = 20, participated also in a football match). Participants trained daily during the two days after the match. Match and training overload was monitored with GPS devices. Venous blood was sampled and muscle damage was assessed pre-match, post-match and at 12h, 36h and 60h post-match. Isometric strength as well as eccentric and concentric peak torque of knee flexors and extensors in both limbs (dominant and non-dominant) were measured on an isokinetic dynamometer at baseline and at 12h, 36h and 60h after the match. Functional (KF_ecc/KE_con) and conventional (KF_con/KE_con) ratios were then calculated. Only eccentric peak torque of knee flexors declined at 60h after the match in the control group. In the experimental group: a) isometric strength of knee extensors and knee flexors declined (P<0.05) at 12h (both limbs) and 36h (dominant limb only), b) eccentric and concentric peak torque of knee extensors and flexors declined (P<0.05) in both limbs for 36h at 60°/s and for 60h at 180°/s with eccentric peak torque of knee flexors demonstrating a greater (P<0.05) reduction than concentric peak torque, c) strength deterioration was greater (P<0.05) at 180°/s and in dominant limb, d) the functional ratio was more sensitive to match-induced fatigue demonstrating a more prolonged decline. Discriminant and regression analysis revealed that strength deterioration and recovery may be related to the amount of eccentric actions performed during the match and athletes' football-specific conditioning. Our data suggest that recovery kinetics of knee flexor and extensor strength after a football match demonstrate strength, limb and velocity specificity and may depend on match physical overload and players' physical conditioning level.

The effects of static stretching on speed and agility: One or multiple repetition protocols?

Although static stretching (SS) is utilized during warm-up before training and competition, the results about its effects on performance remain controversial. We examined whether performing a stretch of short-to-moderate duration (<60 sec) in a single repetition produces a similar or different effect on speed and agility performance from the effect which is produced while performing the same stretch in multiple repetitions of the same total duration. According to a repeated measurement design, 40 trained males were randomly assigned to either (1) a single repetition group or (2) a multiple repetition group. The participants in each group performed five trials: a control trial (no stretches were performed) and four experimental trials of SS protocols consisting of five exercises performed at either 20 sec (2 × 10 in the second group), 30 sec (3 × 10 in the second group), 40 sec (4 × 10 in the second group) or 60 sec (6 × 10 in the second group) of total duration. A two-way repeated measures analysis of variance showed that the participants in both group improved their speed performance in response to the 20-sec trial, whereas agility remained unaffected. Data analysis also revealed that the repetition number did not affect speed and agility performance. These data suggest that SS of short duration (<30 sec) may actually improve acute speed performance, whereas SS of moderate duration may not hamper speed and agility performance. Moreover, the effects of SS protocols are related to the total duration of each exercise and not to the number of repetitions in which each exercise is performed.

Age-related responses in circulating markers of redox status in healthy adolescents and adults during the course of a training macrocycle

Redox status changes during an annual training cycle in young and adult track and field athletes and possible differences between the two age groups were assessed. Forty-six individuals (24 children and 22 adults) were assigned to four groups: trained adolescents, (TAD, N = 13), untrained adolescents (UAD, N = 11), trained adults (TA, N = 12), and untrained adults (UA, N = 10). Aerobic capacity and redox status related variables [total antioxidant capacity (TAC), glutathione (GSH), catalase activity, TBARS, protein carbonyls (PC), uric acid, and bilirubin] were assessed at rest and in response to a time-trial bout before training, at mid- and posttraining. TAC, catalase activity, TBARS, PC, uric acid, and bilirubin increased and GSH declined in all groups in response to acute exercise independent of training status and age. Training improved aerobic capacity, TAC, and GSH at rest and in response to exercise. Age affected basal and exercise-induced responses since adults demonstrated a greater TAC and GSH levels at rest and a greater rise of TBARS, protein carbonyls, and TAC and decline of GSH in response to exercise. Catalase activity, uric acid, and bilirubin responses were comparable among groups. These results suggest that acute exercise, age, and training modulate the antioxidant reserves of the body.

The repeated bout effect of typical lower body strength training sessions on sub-maximal running performance and hormonal response

PURPOSE

This study examined the effects of two typical strength training sessions performed 1 week apart (i.e. repeated bout effect) on sub-maximal running performance and hormonal.

METHODS

Fourteen resistance-untrained men (age 24.0 ± 3.9 years; height 1.83 ± 0.11 m; body mass 77.4 ± 14.0 kg; VOpeak 48.1 ± 6.1 M kg(-1) min(-1)) undertook two bouts of high-intensity strength training sessions (i.e. six-repetition maximum). Creatine kinase (CK), delayed-onset muscle soreness (DOMS), counter-movement jump (CMJ) as well as concentrations of serum testosterone, cortisol and testosterone/cortisol ratio (T/C) were examined prior to and immediately post, 24 (T24) and 48 (T48) h post each strength training bout. Sub-maximal running performance was also conducted at T24 and T48 of each bout.

RESULTS

When measures were compared between bouts at T48, the degree of elevation in CK (-58.4 ± 55.6 %) and DOMS (-31.43 ± 42.9 %) and acute reduction in CMJ measures (4.1 ± 5.4 %) were attenuated (p < 0.05) following the second bout. Cortisol was increased until T24 (p < 0.05) although there were no differences between bouts and no differences were found for testosterone and T/C ratio (p > 0.05). Sub-maximal running performance was impaired until T24, although changes were not attenuated following the second bout.

CONCLUSIONS

The initial bout appeared to provide protection against a number of muscle damage indicators suggesting a greater need for recovery following the initial session of typical lower body resistance exercises in resistance-untrained men although sub-maximal running should be avoided following the first two sessions.