The oral contraceptive cycle and its influences on maximal and submaximal endurance parameters in elite handball players.

The usage of the oral contraceptive pill is widespread among athletes of various levels. However, there is limited knowledge on how the intake of the pill alters the submaximal and maximal endurance parameters between the oral contraceptive phases. Therefore, the aim of this study was to examine potential differences between the pill intake and withdrawal phase on endurance-related parameters in first-division handball players. In total, 15 female team handball players performed two graded exercise tests until volitional exhaustion on a motorized treadmill. Tests were performed during the pill intake (days 16-17) and withdrawal phase (day 2-3). Throughout the test, respiratory gases were measured breath-by-breath, and the heart rate was measured continuously. Before and after the graded exercise test, blood samples were obtained in order to assess the blood lactate concentration. Before each test, venous blood samples were taken to determine endogenous sex hormone levels. Ventilatory parameters (V˙O2, V˙CO2, and V˙E, and respiratory equivalents for V˙O2 and V˙CO2) were measured, and the oxidation of fat and carbohydrates was calculated. A paired-sample t-test was used to assess differences between the two time points, and the significance was accepted as p < 0.050. Significant differences with lower values during the consumption phase were found for absolute (mean difference ± SD: 88 ± 131 mL∙min-1; p = 0.021) and relative V˙O2peak (mean difference ± SD: 1 ± 2 mL∙min-1∙kg-1; p = 0.012). Higher values during the consumption phase were found for submaximal respiratory equivalents for V˙O2 (mean difference ± SD: -1.1 ± 1.7; p = 0.028) and V˙CO2 (mean difference ± SD: -0.9 ± 1.5; p = 0.032). No differences were found for all other parameters, including differences for endogenous sex hormones (p > 0.050). The results of the current study suggest only marginal and physiologically insignificant differences in endurance-related parameters between oral contraceptive phases.

Body Composition of Competitive Bodybuilders: A Systematic Review of Published Data and Recommendations for Future Work.

ABSTRACT: Bauer, P, Majisik, A, Mitter, B, Csapo, R, Tschan, H, Hume, P, Martínez-Rodríguez, A, and Makivic, B. Body composition of competitive bodybuilders: a systematic review of published data and recommendations for future work. J Strength Cond Res 37(3): 726-732, 2023-The purpose of this review was to systematically summarize studies measuring the body composition of competitive bodybuilding athletes to provide recommended values for preparation and during competition. The protocol was preregistered with PROSPERO (CRD42020197921) and followed the guidelines of the Preferred Reported Items for Systematic Reviews and Meta-Analysis. A search of 5 electronic databases (PubMed, Web of Science, SportDiscus, CINAHL, and Scopus) was conducted to retrieve all relevant publications from January 1, 2000, up to June 13, 2021. Of 16 studies meeting the inclusion criteria, 6 presented longitudinal data on competition preparation and were discussed in detail. In the general preparation phase, body fat levels of bodybuilding athletes ranged between 15.3 and 25.2% (female) and from 9.6 to 16.3% (male). Close to competition, however, body fat levels were substantially lower, ranging from 8.1 to 18.3% for female and 5.8-10.7% for male athletes. All studies comparing relative body fat values at various time points during competition preparation found significant reductions between 30 and 60% in relative body fat, whereas lean mass was mostly maintained. Findings from the studies included in this review suggest that most bodybuilding competitors keep resistance training volume high while increasing aerobic training volume when preparing for competition. Findings on energy intake and macronutrient distribution were unclear and should be addressed in future studies. Further research, especially on contest preparation, is warranted and should include more details about training programs, nutritional strategies, psychosocial situation, anabolic androgen steroid, and supplement use as well as measurement protocols and preparation.

Modelling the relationship between load and repetitions to failure in resistance training: A Bayesian analysis.

To identify the relationship between load and the number of repetitions performed to momentary failure in the pin press exercise, the present study compared different statistical model types and structures using a Bayesian approach. Thirty resistance-trained men and women were tested on two separate occasions. During the first visit, participants underwent assessment of their one-repetition maximum (1-RM) in the pin press exercise. On the second visit, they performed sets to momentary failure at 90%, 80% and 70% of their 1-RM in a fixed order during a single session. The relationship between relative load and repetitions performed to failure was fitted using linear regression, exponential regression and the critical load model. Each model was fitted according to the Bayesian framework in two ways: using an across-subjects pooled data structure and using a multilevel structure. Models were compared based on the variance explained (R2) and leave-one-out cross-validation information criterion (LOOIC). Multilevel models, which incorporate higher-level commonalities into individual relationships, demonstrated a substantially better fit (R2: 0.97-0.98) and better predictive accuracy compared to generalised pooled-data models (R2: 0.89-0.93). The multilevel 2-parameter exponential regression emerged as the best representation of data in terms of model fit, predictive accuracy and model simplicity. The relationship between load and repetitions performed to failure follows an individually expressed exponential trend in the pin press exercise. To accurately predict the load that is associated with a certain repetition maximum, the relationship should therefore be modelled on a subject-specific level.

Impact of Using Population-Specific Cut-Points, Self-Reported Health, and Socio-Economic Parameters to Predict Sarcopenia: A Cross-Sectional Study in Community-Dwelling Kosovans Aged 60 Years and Older.

The age-related decline of muscle strength, mass, and physical performance (sarcopenia) has been raising concerns among the scientific and healthcare communities. This decline may differ between populations, age groups, and sexes. Therefore, we aimed to explore sarcopenia together with the impact of health and socio-economic parameters in mature Kosovans. A cross-sectional study was conducted on community-dwelling adults aged ≥ 60 years (n = 240, 47.1% female) from the Prishtina region. Sarcopenia was identified using the following criteria: (i) the European Working Group in Sarcopenia for Older People (EWGSOP1), (ii) the revised EWGSOP2 algorithms, and (iii) sex-specific cut-points derived from the Kosovan population. In males, pre-sarcopenia/probable sarcopenia was detected from the EWGSOP1, EWGSOP2 and Kosovan-specific criteria at values of 3.1%, 5.5%, and 28.3%; sarcopenia was detected at 1.6%, 5.5%, and 0.0%, and severe sarcopenia was detected at 4.7%, 2.4%, and 4.7%, respectively. Pre-sarcopenia was lower in females (0.9%, 5.3%, 16.8%), with no cases of sarcopenia or severe sarcopenia detected by either algorithm. Sarcopenic males were older, had a lower weight, BMI, skeletal muscle mass, performance score, nutritional status (p < 0.001), educational level (p = 0.035), and higher malnourishment risk (p = 0.005). It is notable that high overweight and obesity levels were also detected (93.8% of females, 77.1% of males). This study highlights the importance of using population-specific cut-points when diagnosing sarcopenia, as otherwise its occurrence may be underestimated, especially in obese persons. Age, body composition, physical performance, health, and socio-economic conditions can influence the occurrence of sarcopenia.

Does a Physical Activity Intervention on Classroom-Based Ergometers During Teaching Lessons Effect Physical Fitness, Body Composition, and Health-Related Blood Parameters? A Pilot Cluster Randomized Controlled Study.

BACKGROUND: Time constraints comprise one limiting factor for implementing school-based physical activity programs. The aim of this pilot cluster randomized controlled study was to explore the effects of a cycle ergometer intervention during regular lessons on physical fitness, body composition, and health-related blood parameters. METHODS: Participants attended one of 2 classes selected from one school, which were randomly assigned to an intervention group (n = 23, 11.2 [0.5] y) consisting of cycling on classroom-based ergometers during 3 lessons per week at a self-selected intensity and a control group (n = 21, 11.3 [0.5] y) not receiving any treatment. Prior to and after the 5-month intervention period, physical fitness (with ventilatory threshold as primary outcome), body composition, and parameters of glucose and lipid metabolism were assessed. RESULTS: A significant time × group interaction was revealed for ventilatory threshold (P = .035), respiratory compensation point (P = .038), gross efficiency (P < .001), maximal aerobic power (P = .024), triglycerides (P = .041), and blood glucose levels (P = .041) with benefits for the intervention group. Peak oxygen uptake and body composition were not affected. CONCLUSIONS: Children's aerobic capacity benefited from the low-intensity school-based cycling intervention, while body composition and most blood parameters were not affected. The intervention using cycle ergometers is a feasible and time-saving strategy to elevate submaximal physical fitness.

Agility and change-of-direction speed are two different abilities also during the execution of repeated trials and in fatigued conditions.

Agility and change of direction speed are two different abilities, but no study has investigated if this difference exists also in fatigued conditions, and whether fatigue develops in a different way in a repeated-trial scenario. Fourteen soccer players (age: 17.0 ± 0.4 yrs; height: 176.9 ± 6.5 cm; body mass: 69.2 ± 6.4 kg) competing in a national-level youth league completed in a randomized counter-balanced crossover design a repeated agility protocol (RA) and a repeated change-of-direction one (RCOD), both consisting in performing 20 consecutive repetitions (work:rest ratio 1:5). The 20 repetitions were divided into 4 blocks (each block containing 5 repetitions) for the analysis. Results show that agility and COD are two different abilities both in rest and fatigue conditions: block 1 RA vs 1 RCOD (p < 0.001; ES = 2.02 huge; r = 0.17 poor; r2 = 0.03), 2 RA vs 2 RCOD (p < 0.001; ES = 2.3 huge; r = 0.51 fair; r2 = 0.26), 3 RA vs 3 RCOD (p < 0.001; ES = 2.38 huge; r = 0.54 fair; r2 = 0.29), and 4 RA vs 4 RCOD (p < 0.001; ES = 2.7 huge; r = 0.41 fair; r2 = 0.17). However, the fatigue development in both conditions was similar, with a percentage decrement score (Sdec) of 7.5% for RA, and 7.3% for RCOD. Ratings of perceived exertions (RPE) were similar too (7.3 ± 1.7, and 6.6 ± 1.9, for RA and RCOD, respectively). However, a significant fatigue-related performance impairment arose earlier in RA (block 2) than in RCOD (block 3). Total RA and total RCOD times were significantly different (p < 0.001; ES = 2.65 huge; r = 0.41 fair; r2 = 0.17), suggesting that they are two different and independent abilities.

Reproducibility of strength performance and strength-endurance profiles: A test-retest study.

The present study was designed to evaluate the test-retest consistency of repetition maximum tests at standardized relative loads and determine the robustness of strength-endurance profiles across test-retest trials. Twenty-four resistance-trained males and females (age, 27.4 ± 4.0 y; body mass, 77.2 ± 12.6 kg; relative bench press one-repetition maximum [1-RM], 1.19 ± 0.23 kg•kg-1) were assessed for their 1-RM in the free-weight bench press. After 48 to 72 hours, they were tested for the maximum number of achievable repetitions at 90%, 80% and 70% of their 1-RM. A retest was completed for all assessments one week later. Gathered data were used to model the relationship between relative load and repetitions to failure with respect to individual trends using Bayesian multilevel modeling and applying four recently proposed model types. The maximum number of repetitions showed slightly better reliability at lower relative loads (ICC at 70% 1-RM = 0.86, 90% highest density interval: [0.71, 0.93]) compared to higher relative loads (ICC at 90% 1-RM = 0.65 [0.39, 0.83]), whereas the absolute agreement was slightly better at higher loads (SEM at 90% 1-RM = 0.7 repetitions [0.5, 0.9]; SEM at 70% 1-RM = 1.1 repetitions [0.8, 1.4]). The linear regression model and the 2-parameters exponential regression model revealed the most robust parameter estimates across test-retest trials. Results testify to good reproducibility of repetition maximum tests at standardized relative loads obtained over short periods of time. A complementary free-to-use web application was developed to help practitioners calculate strength-endurance profiles and build individual repetition maximum tables based on robust statistical models.

A Video-Based Tactical Task Does Not Elicit Mental Fatigue and Does Not Impair Soccer Performance in a Subsequent Small-Sided Game.

Mental fatigue can impair physical, technical, and tactical performance in sports. Since most previous research used general cognitive tasks to elicit mental fatigue, the aim of this study was to investigate whether a more sport-specific task could induce the effects of mental fatigue and impair the subsequent physical and technical performance in a soccer small-sided game. Ten soccer players performed two small-sided games on two different days in a crossover design. Before each small-sided game, they performed a video-based tactical task (30 min) and a control task (documentary watching, 30 min) in a randomized and counterbalanced order. Mental effort was measured through a visual analog scale after the tactical and control tasks. Subjective ratings of perceived exertion were assessed through the RPE questionnaire after the end of the SSG. Physical performance was assessed during the SSG through GPS technology. Results showed no differences (p > 0.05) in physical performance between the two conditions. None of the technical variables were negatively affected by the video-based tactical condition, with the number of total passes (p = 0.003; ES = 0.72 medium) and successful passes (p = 0.003; ES = 0.82 large) results even improved by the video-based tactical task. The mental effort required by the video-tactical task was significantly higher than the control task (p = 0.002; ES = 2.09 huge). However, overall RPE did not differ between conditions. The video-based tactical task did not elicit mental fatigue and did not impair subsequent physical and technical performance. The higher ecological validity of the task and the higher motivation of the participants might have contributed to the results.

Effects of Post-Activation Performance Enhancement (PAPE) Induced by a Plyometric Protocol on Deceleration Performance.

Post-Activation Potentiation (PAP) is a phenomenon which can improve power performance executed after a previous conditioning activity. PAP is usually evoked through heavy resistance or plyometric exercise. It has been suggested to refer to as Postactivation Performance Enhancement (PAPE) when research is field-based on explosive activities. To our best knowledge, no studies have investigated the effects of PAPE on deceleration performance, which is a key factor in sports involving change of directions. Therefore, the aim of this study was to investigate the influence of a plyometric exercise protocol on a subsequent deceleration running performance. University soccer players (n = 18) performed seven deceleration trials and were assessed at baseline and after ~15 s, 2, 4, 8, 12 and 16 min either following a walking control condition (C) or three sets of ten repetitions of alternate-leg bounding (plyometric, P). Results showed no significant differences at any of the trials under the control condition (C) in comparison to the relative baseline. Under the plyometric condition (P), deceleration performance executed two minutes after the plyometric activity resulted in significantly faster results compared to the baseline values (p = 0.042; ES = 0.86, large effect; % of improvement = 4.13 %). The main findings are that plyometric exercise improves a subsequent running deceleration performance, 2 min after its execution. Future investigations should focus on more complex actions such as changes of direction and agility.

Influence of an increased number of physical education lessons on the motor performance of adolescents-A non-interventional cohort study.

Increasing the amount of regular physical education lessons in school is currently discussed in many countries in order to increase physical activity in youth. The purpose of this study was to compare the motor performance of pupils from an observation group participating in a school trial of two additional physical education lessons (5 lessons of each 50 min/week) without a specific intervention program to a control group with a regular amount of three physical education lessons (3 lessons of each 50 min/week) as indicated by the standard Austrian school curriculum. In this cohort study motor performance of 140 adolescents (12.7±0.5 years) was assessed by means of the German Motor Performance Test 6-18 over a period of 1.5 years with measurement time points before (T1), after eight months (T2) and at the end of the observation period (T3). Two- and three-way mixed analysis of variance were used to detect time, group and interaction effects. Although the observation group demonstrated a higher total motor performance score at all time points (P = 0.005), the improvement over time in total motor performance (P < 0.001) was more pronounced in the control group. Girls and boys developed differently over time (time*gender interaction: P = 0.001), whereby group allocation did not affect this interaction (time*gender*group: P = 0.167). Anyway, girls of control group tend to benefit most of additional physical education lessons. Sports club members scored significantly higher in motor performance across the observation period (P = 0.018) irrespective of group allocation. These findings indicate that there could be a ceiling effect in what the pupils could achieve in terms of motor performance as the pupils of the observation group might have reached this point earlier than their counterparts in the control group. Nevertheless, sports club membership seems to reveal some benefits. Whether improving quality and specificity of the single physical lessons might be superior to merely adding additional ones needs to be confirmed in future studies.

ACTN3 Genotypes and Their Relationship with Muscle Mass and Function of Kosovan Adults.

Maintaining muscle mass and function is important throughout the lifestyle. While environmental factors such as physical activity and healthy nutrition are well investigated, the contribution of genetic factors is still controversial. Therefore, we aimed to investigate the impact of a common ACTN3 polymorphism (rs1815739) on body composition, handgrip strength, knee extensor peak torque, and physical performance (gait speed, 30-s arm curl, 30-s chair stand) in Kosovan adults. In total, 308 participants (160 females and 148 males, age range from 40 to 91 years) took part in this cross-sectional study. Genomic DNA was extracted from saliva and assessed for ACTN3 genotype distribution (41.5% of RR, 53.9% of RX and 4.6% of XX). Genotype allocation did not account for differences in any of the variables. Interestingly, female XX carriers were taller (p = 0.025) and had a higher isokinetic knee extension peak torque (p = 0.024) than the RX+RR group. In males, XX carriers were also taller (p = 0.049) and had a lower BMI (p = 0.026), but did not differ in any of the strength and performance parameters. These results indicate that the ACTN3 R577X polymorphism might exert a sex-specific impact on knee extensor peak torque and BMI.

Strength Performance Across the Oral Contraceptive Cycle of Team Sport Athletes: A Cross-Sectional Study.

Oral contraceptive pills (OCP) are very popular in female athletes not only for contraceptive effects but also due to the possibility of cycle manipulation. Moreover, it is debatable whether the manipulation of the menstrual cycle has a beneficial effect on exercise performance. Therefore, the aim of this study was to investigate potential differences in knee-extensor and flexor strength performance of first division team sport athletes between phases of the oral contraceptive cycle. Sixteen female handball players (age: 23.3 ± 3.1 years; body mass: 67.0 ± 8.52 kg; body stature: 1.68 ± 0.05 m) using a monophasic OCP participated in strength performance tests, once during OCP consumption (CONS) and once during withdrawal (WITH). Tests were performed on a dynamometer to measure knee-extensor and flexor maximal voluntary isokinetic and isometric torque. Prior to each test, body mass was assessed, and venous blood samples were collected. Wilcoxon signed-rank test and magnitude-based inferences have been conducted to analyze differences between WITH and CONS. Significance was accepted at P < 0.05. No significant differences between oral contraceptive cycle phases of knee-extensor and flexor strength parameters and body mass have been indicated (all at P > 0.05). Follicle-stimulating hormone (FSH) (P = 0.001) and luteinizing hormone (P = 0.013) were significantly higher in WITH, whereby estradiol and progesterone showed no significant difference between phases (both at P > 0.05). These results support the notion that knee-extensor and flexor isokinetic and isometric strength performance does not differ between phases of oral contraceptive cycle in well-trained team sport athletes. OCP intake is suggested to cause a stable but downregulated hormone cycle, which has no effect on knee-extensor and flexor strength when comparing oral contraceptive cycle phases. Therefore, manipulation of the female cycle using OCP in order to achieve a higher knee-extensor and flexor strength performance does not seem to be justified; however, it is currently unclear if cycle manipulation might affect other physiological systems.

Oxygen Uptake Kinetics in Endurance Trained Youth and Adult Cyclists.

Previous studies reported faster pulmonary oxygen uptake kinetics at the onset of exercise in untrained youth compared with adults. Whether or not these differences are identical for trained groups have not been examined. The purpose of this study was to compare ˙VO2 kinetics of youth and adult cyclists at moderate and heavy-intensity exercise. Thirteen adult (age: 23.2 ± 4.8 years; ˙VO2peak 68.4 ± 6.8 mL·min-1.kg-1) and thirteen youth cyclists (age: 14.3 ± 1.5 years; ˙VO2peak 61.7 ± 4.3 mL·min-1.kg-1) completed a series of 6-min square wave exercises at moderate and heavy-intensity exercise at 90 rev·min-1. A two-way repeated-measure ANOVA was conducted to identify differences between groups and intensities. The time constant, time delay and the mean response time were not significantly different between youth and adult cyclists (p > 0.05). We found significant differences between intensities, with a faster time constant during moderate than heavy-intensity exercise in youth (24.1 ± 7.0 s vs. 31.8 ± 5.6 s; p = 0.004) and adults (22.7 ± 5.6 s vs. 28.6 ± 5.7 s; p < 0.001). The present data suggest that the effect of training history in adult cyclists compensate for the superior primary response of the oxygen uptake kinetics typically seen in youth compared to adults. Furthermore, the ˙VO2 response is dependent of work rate intensity in trained youth and adult cyclists.

Aerobic and Anaerobic Power Distribution During Cross-Country Mountain Bike Racing.

PURPOSE: To determine aerobic and anaerobic demands of mountain bike cross-country racing. METHODS: Twelve elite cyclists (7 males; V˙O2max = 73.8 [2.6] mL·min-1·kg-1, maximal aerobic power [MAP] = 370 [26] W, 5.7 [0.4] W·kg-1, and 5 females; V˙O2max = 67.3 [2.9] mL·min-1·kg-1, MAP = 261 [17] W, 5.0 [0.1] W·kg-1) participated over 4 seasons at several (119) international and national races and performed laboratory tests regularly to assess their aerobic and anaerobic performance. Power output, heart rate, and cadence were recorded throughout the races. RESULTS: The mean race time was 79 (12) minutes performed at a mean power output of 3.8 (0.4) W·kg-1; 70% (7%) MAP (3.9 [0.4] W·kg-1 and 3.6 [0.4] W·kg-1 for males and females, respectively) with a cadence of 64 (5) rev·min-1 (including nonpedaling periods). Time spent in intensity zones 1 to 4 (below MAP) were 28% (4%), 18% (8%), 12% (2%), and 13% (3%), respectively; 30% (9%) was spent in zone 5 (above MAP). The number of efforts above MAP was 334 (84), which had a mean duration of 4.3 (1.1) seconds, separated by 10.9 (3) seconds with a mean power output of 7.3 (0.6) W·kg-1 (135% [9%] MAP). CONCLUSIONS: These findings highlight the importance of the anaerobic energy system and the interaction between anaerobic and aerobic energy systems. Therefore, the ability to perform numerous efforts above MAP and a high aerobic capacity are essential to be competitive in mountain bike cross-country.

Test-retest reliability data of functional performance, strength, peak torque and body composition assessments in two different age groups of Kosovan adults.

This article reports test-retest reliability data of laboratory- and field-based performance tests as well as body composition analyses of younger and older Kosovan adults. In total, 57 healthy young (18-35 years) and 61 older (>60 years) participants took part in two identical test sessions, with a median [25th - 75th percentile] of 14 [13-21] days in between. Functional performance tests included 30-s chair stand test (CST), 30-s arm curl test (ACT), six-minutes walking test (6MWT), sit and reach test, timed up and go test (TUG), as well as the assessment of gait speed (GS) at normal and fast pace. Isometric handgrip strength (HGS) was used to estimate strength of the dominant hand. Isokinetic peak torque (PT) and average power (AvgP) for knee extension and flexion were determined at velocities of 60°/s and 120°/s. Body composition assessments included body fat percentage, skeletal muscle mass (SMM) and index (SMI) as well as appendicular skeletal muscle mass (ASMM) and index. Secondary endpoints included self-perceived health status and potential co-morbidities. All performance test outcomes as well as body fat percentage, SMM, ASMM, and self-perceived health were significantly better in young as compared to older participants (p < 0.001). Improvements from test to retest were observed for CST (p < 0.001), PTflexion (60°/s: p = 0.001, 120°/s: p = 0.041), AvgPflexion (60°/s: p < 0.001, 120°/s: p < 0.001), AvgPextension (120°/s: p = 0.050), but also for SMM (p = 0.021) and SMI (p = 0.021). Only for CST and HGS a time x age group interaction was detected (p < 0.05). Acceptable reliability (ICC > 0.7) was observed for all parameters in both age groups, except for some of the measures from the isokinetic dynamometry, where ICCs were generally lower in older participants, but fell below 0.7 for AvgPflexion at 60°/s (ICC = 0.6) and at 120°/s (ICC = 0.67) as well as for PTflexion at 120°/s (ICC = 0.69). These data's importance lay upon their potential use in epidemiological studies observing muscle strength, peak torque, power, physical performance and body composition over various age groups, either in the same or similar populations, or for comparison to other populations.

Internal, external and repeated-sprint demands in small-sided games: A comparison between bouts and age groups in elite youth soccer players.

This study investigated the activity profile during small-sided games (SSG) in elite youth soccer players. Internal load (IL) including heart rate (HR) and external load (EL) such as distance covered in different speed-zones (SZ) were collected from forty-eight players of three different teams (U15, U16, U18). The investigation included a total of eighteen 5vs.5 SSGs, each consisting of four 2-minute bouts on a 40x32m pitch during spring season. Total group results (n = 48) showed a reduction in total-distance (p = 0.001; [Formula: see text] = 0.12), high-intensity-running (p = 0.009; [Formula: see text] = 0.09), and low-intensity-running distance (p = 0.028; [Formula: see text] = 0.07) between bouts. Similarly, a reduction in the number of both acceleration-low (p = 0.001; [Formula: see text] = 0.12) and deceleration-high (p = 0.003; [Formula: see text] = 0.11) values was observed. Additionally, time spent in HR-zones 3 and 4 (p≤0.007; [Formula: see text] ≥ 0.10), increased, with a reduction in HR-zone 1 (p = 0.000, [Formula: see text] = 0.25). Age group comparison showed less distance covered in SZ 1 (p≤0.000; [Formula: see text] = 0.56) and greater deceleration-high values (p≤0.038; [Formula: see text] = 0.32) in U15 players compared to other age groups. Further, U15 showed lower values in low-intensity-running compared to U18 (p = 0.038; [Formula: see text] = 0.22). No age-related differences were found for IL and repeated sprint ability (RSA) values. The higher EL in younger age groups should be taken into account when implementing soccer specific SSGs. In addition, HRmean values between 80-85% of HRmax and RSA numbers, which are similar to match-play data, indicate SSGs as an effective training tool to prepare youth soccer athletes for the demands of competition.

A 30-Min Rest Protocol Does Not Affect W', Critical Power, and Systemic Response.

PURPOSE: This study aimed to assess and compare the systemic response of oxygen uptake kinetics and muscle deoxygenation between a 30-min rest protocol and a multivisit protocol on the parameters of the power-duration relationship (i.e., critical power [CP] and W'). METHODS: Nine endurance-trained triathletes reported to the laboratory on five occasions: a preliminary graded exercise test and a familiarization, a 30-min single-visit protocol (time trials of 10, 5, and 2 min in that order interspersed with 30 min rest), and a multivisit protocol (time trials of 10, 5, and 2 min in randomized order interspersed by >24 h rest). Heart rate (HR) was recorded continuously, respiratory gases were measured breath by breath, and deoxygenation was recorded at 10 Hz using near-infrared spectroscopy (NIRS) during all tests. Blood lactate (BLa-) concentration was measured before all time trials. Maximal HR (HRmax), oxygen uptake (V˙O2) during the first 2 min (V˙O2onset), mean response time, end-exercise V˙O2 (V˙O2peak), V˙O2 amplitude (amplV˙O2), O2 deficit, NIRS τ, amplitude (amplNIRS), and time delay were assessed. To compare the two protocols and to assess the differences in W' and CP, a paired sample t-test was used as well as a two-way ANOVA to assess the differences between trials and/or protocols, including trial-protocol interactions. RESULTS: No significant differences, and trivial effect sizes, were found for W' and CP between protocols (P = 0.106-0.114, d < 0.01-0.08). Furthermore, no significant differences between protocols were found for all parameters, except for [BLa-]. Significant differences between trials were found for V˙O2ampl, V˙O2onset, NIRS τ, amplNIRS, [BLa-], and HRmax. CONCLUSION: Results suggest that W' and CP can be determined using the 30-min rest protocol without confounding effects of previous severe exercise compared with the multivisit protocol.

Concurrent Validity of Field-Based Diagnostic Technology Monitoring Movement Velocity in Powerlifting Exercises.

ABSTRACT: Mitter, B, Hölbling, D, Bauer, P, Stöckl, M, Baca, A, and Tschan, H. Concurrent validity of field-based diagnostic technology monitoring movement velocity in powerlifting exercises. J Strength Cond Res 35(8): 2170-2178, 2021-The study was designed to investigate the validity of different technologies used to determine movement velocity in resistance training. Twenty-four experienced powerlifters (18 male and 6 female; age, 25.1 ± 5.1 years) completed a progressive loading test in the squat, bench press, and conventional deadlift until reaching their 1 repetition maximum. Peak and mean velocity were simultaneously recorded with 4 field-based systems: GymAware (GA), FitroDyne (FD), PUSH (PU), and Beast Sensor (BS). 3D motion capturing was used to calculate specific gold standard trajectory references for each device. GA provided the most accurate output across exercises (r = 0.99-1, ES = -0.05 to 0.1). FD showed similar results for peak velocity (r = 1, standardized mean bias [ES] = -0.1 to -0.02) but considerably less validity for mean velocity (r = 0.92-0.95, ES = -0.57 to -0.29). Reasonably valid to highly valid output was provided by PU in all exercises (r = 0.91-0.97, ES = -0.5 to 0.28) and by BS in the bench press and for mean velocity in the squat (r = 0.87-0.96, ES = -0.5 to -0.06). However, BS did not reach the thresholds for reasonable validity in the deadlift and for peak velocity in the squat, mostly due to high standardized mean bias (ES = -0.78 to -0.63). In conclusion, different technologies should not be used interchangeably. Practitioners who require negligible measurement error in their assessment of movement velocity are advised to use linear position transducers over inertial sensors.

Activity Profile of International Female Lacrosse Players.

ABSTRACT: Hauer, R, Tessitore, A, Hauer, K, and Tschan, H. Activity profile of international female lacrosse players. J Strength Cond Res 35(11): 3207-3212, 2021-This study was designed to investigate the activity profile in international women's lacrosse match-play. Data were collected of 10 female Austrian lacrosse national team players (29.1 ± 6.1 years; 64.2 ± 5.0 kg; and 165.3 ± 4.1 cm) during 4 games of an international tournament using global positioning system and heart rate monitor devices. The mean average heart rate was 75.3 ± 5.0% of maximum heart rate (HRmax) with 23 ± 6.1% of total playing time spent in HRzone 4 (80-90% of HRmax). The mean distance covered during match-play was 3,791.6 ± 554.5 m, of which 38 ± 6.5% were performed in speed zone 1 (<7.0 km·h-1). Ten ±4 sprints per game were conducted with 55 ± 3.8% of accelerations and 59 ± 3.1% of decelerations in zone 1, respectively. Defenders showed greater total distance covered compared with other positions (attack: p = 0.035; d = 0.87; confidence interval [CI] = 0.18-1.56 and midfield: p = 0.006; d = 1.66; CI = 0.93-2.40). Midfielders covered less distance in speed zone 1 (p = 0.032; d = 1.91; CI = 0.53-3.28) compared with attackers, and lower numbers of accelerations (p = 0.042; d = 0.96; CI = 0.20-1.72) and decelerations (p = 0.021; d = 1.79; CI = 0.61-2.97) in zone 3 compared with defenders. Furthermore, attackers showed less distance covered in speed zone 1 (p = 0.09; d = 1.62; CI = 0.86-2.38) compared with defenders. The provided activity data could help coaches and practitioners in designing competition-specific programs for athletes. In addition, positional differences should be taken into account for tactical and physiological aspects.

Potential prognostic factors for hamstring muscle injury in elite male soccer players: A prospective study.

Hamstring injuries remain the most common injury type across many professional sports. Despite a variety of intervention strategies, its incidence in soccer players playing in the UEFA Champions League has increased by 4% per year over the last decade. Test batteries trying to identify potential risk factors have produced inconclusive results. The purpose of the current study was to prospectively record hamstring injuries, to investigate the incidence and characteristics of the injuries, and to identify possible risk factors in elite male soccer players, playing in the Kosovo national premier league. A total of 143 soccer players from 11 teams in Kosovo were recruited. To identify possible prevalent musculoskeletal or medical conditions a widespread health and fitness assessment was performed including isokinetic strength testing, Nordic hamstring strength test, functional tests, and a comprehensive anamnesis surveying previous hamstring injuries. On average 27.9% of the players sustained at least one hamstring injury with three players suffering bilateral strains with the re-injury rate being 23%. Injured players were significantly older and heavier and had a higher body mass index compared to non-injured ones (p < 0.05). There was a lower passing rate in the Nordic hamstring strength test and a higher injury incidence among the previously injured players compared to non-injured ones (p < 0.05). Except for hamstring/quadriceps ratio and relative torque at 60°/sec (p < 0.05) for dominant and non-dominant leg, there were no other significant differences in isokinetic strength regardless of the angular velocity. No differences were observed for functional tests between cohorts. Regression analysis revealed that age, Nordic hamstring strength test, previous injury history, and isokinetic concentric torque at 240°/sec could determine hamstring injuries by 25.9%, with no other significant predicting risk factors. The battery of laboratory and field-based tests performed during preseason to determine performance related skills showed limited diagnostic conclusiveness, making it difficult to detect players at risk for future hamstring injuries.