Long-Term Rowing Performance Development in Male Olympic and World Championship Medal Winners Compared With Nonmedalists.

ABSTRACT: Mäestu, J, Lelle, R, Mäestu, E, Pind, R, Vahtra, E, Purge, P, and Mikulic, P. Long-term rowing performance development in male Olympic and World Championship medal winners compared with nonmedalists. J Strength Cond Res 37(9): e521-e526, 2023-The purpose of this study was, first, to investigate individual longitudinal 2,000 m rowing ergometer performance (2,000 erg) development of world class male rowers from the beginning of their career until reaching the elite level and to compare ELITE performance development with those who did not reach podium places and, second, to provide 2,000 erg milestones for talent prediction in rowing. Individual annual 2,000 erg performances of 54 male rowers were analyzed from age 15 and throughout their career. Olympic or World Championships medal winners (ELITE; n = 11) were compared with those who did not reach international podium places. Two thousand erg increased ( p ≤ 0.05) until the age of 24 in ELITE, while plateaued earlier for less successful rowers. No differences in the rate of performance improvement were found between ELITE and lower performers ( p > 0.05). At the age of 20, performance between ELITE and international level nonmedal winners reached significant difference (480.7 ± 20.9 W vs. 435.3 ± 33.9 W, respectively) and remained different onwards ( p ≤ 0.05). However, the average of the 10 best seasons cross-sectional performances of less successful rowers were significantly higher until age 18, compared with ELITE. ELITE rowers were able to improve their 2,000 erg performance to higher age; therefore, it is difficult to predict elite performers in junior rowers. Cross-sectional performances of less successful rowers may indicate temporary high-level performers, who might not be able to advance the elite level.

Effects of caffeine on rate of force development: A meta-analysis.

This review aimed to conduct a meta-analysis of studies examining the effects of caffeine on rate of force development (RFD). Ten databases were searched to find relevant studies. Risk of bias (RoB) of the included studies was evaluated. Data were analyzed in a random-effects meta-analysis. Eleven studies with "some concerns" regarding RoB were included. In the main meta-analysis, there was a significant ergogenic effect of caffeine ingestion on RFD (Hedges' g = 0.37; 95% confidence interval [CI]: 0.21, 0.52; p < 0.0001). An ergogenic effect of caffeine was also found on RFD during resistance exercises (Hedges' g = 0.49; 95% CI: 0.30, 0.67; p < 0.0001), but not during the countermovement jump test (Hedges' g = 0.18; 95% CI: -0.02, 0.39; p = 0.08), with a significant difference between the subgroups (p = 0.03). Small-to-moderate (3-5 mg/kg; Hedges' g = 0.25; 95% CI: 0.09, 0.41; p = 0.002) and moderate-to-high caffeine doses (6-10 mg/kg) enhanced RFD (Hedges' g = 0.57; 95% CI: 0.30, 0.85; p < 0.0001), even though the effects were larger with higher caffeine doses (p = 0.04). Overall, caffeine ingestion increases RFD, which is relevant given that RFD is commonly associated with sport-specific tasks. From a practical perspective: (1) individuals interested in the acute enhancement of RFD in resistance exercise may consider supplementing with caffeine; and (2) given that evaluation of RFD is most commonly used for testing purposes, caffeine ingestion (3-10 mg/kg 60 min before exercise) should be standardized before RFD assessments.

Test-retest reliability of isometric mid-thigh pull maximum strength assessment: a systematic review.

The aim of this systematic review was to explore the test-retest reliability of isometric mid-thigh pull maximum strength assessment. We searched through five databases to find studies that examined the test-retest reliability of peak force in the isometric mid-thigh pull exercise. From each included study, we extracted intra-class correlation coefficients (ICC) and/or coefficient of variation (CV). The methodological quality of the included studies was evaluated using the COSMIN checklist. A total of 16 good-to-excellent quality studies were included in the review. When considering results from all included studies, ICCs ranged from 0.73 to 0.99 (median ICC = 0.96), where 78% of ICCs were ≥ 0.90, and 98% of ICCs were ≥ 0.75. The range of reported CVs was from 0.7% to 11.1% (median CV = 4.9%), where 58% of CVs were ≤ 5%. Reliability was also good-to-excellent for both relative and absolute peak force and for both bilateral and unilateral isometric mid-thigh pull tests. The majority of studies did not find significant differences between testing sessions. It can be concluded that the isometric mid-thigh pull maximum strength assessment has good-to-excellent test-retest reliability. The isometric mid-thigh pull maximum strength assessment can be used as a reliable test in sports practice and for research purposes.

CYP1A2 genotype and acute ergogenic effects of caffeine intake on exercise performance: a systematic review.

PURPOSE: To systematically review studies that examined the influence of the CYP1A2 -163C>A polymorphism on the ergogenic effects of caffeine and to discuss some of the reasons for the discrepancies in findings between the studies. METHODS: This review was performed in accordance with the PRISMA guidelines. The search for studies was performed through nine databases. RESULTS: Seventeen studies were included in the review. Based on the included studies, it seems that individuals with the AA or AC/CC genotype may experience an increase in performance following caffeine ingestion. Significant differences between genotypes were found in four studies, and all four reported a more favorable response in the AA vs. AC/CC genotype. These results suggest that if there is an actual genotype-related effect of acute caffeine supplementation, it might be in that direction. In the studies that reported such data for aerobic endurance, the findings are specific to male participants performing cycling time trials (distances of ≥ 10 km) and ingesting caffeine 60 min before exercise. For high-intensity exercise, two studies reported that genotype variations determined the response to caffeine ingestion, even though the differences were either small (~ 1 additional repetition in high-load resistance exercise set performed to muscular failure) or inconsistent (i.e., observed only in one out of eight performance tests). CONCLUSIONS: CYP1A2 genotype variations may modulate caffeine's ergogenic effects, but the differences between genotypes were small, inconsistent, or limited to specific exercise scenarios. Future studies with larger sample sizes are needed to fully elucidate this research area.

Effects of 8-Week Jump Training Program on Sprint and Jump Performance and Leg Strength in Pre- and Post-Peak Height Velocity Aged Boys.

The purpose of this study was: (a) to determine the effects of an 8-week jump training program on measures of neuromuscular performance in 12-14-year-old boys before and after peak height velocity (PHV), and (b) to compare the effects of the jump training program to the effects of the regular physical education program. One hundred and twenty-six participants were categorized into two maturity groups (pre- or post-PHV) and then randomly assigned to either a jump training (pre-PHV, n = 26; post-PHV, n = 24) or a control (pre-PHV, n = 33; post-PHV, n = 19) group. Jump training consisted of twice-weekly training for 8 weeks, while control groups continued with their regular physical education lessons. Squat jump and countermovement jump height (cm), reactive strength index (the ratio between jump height and ground contact time (mm/ms)), 20-m sprint time (s), and isokinetic knee extensors muscle strength (peak toque (Nm)) were assessed pre- and post-intervention. Following the 8-week intervention, both pre- and post-PHV jump training groups made significant gains in measures of neuromuscular performance irrespective of the maturity (where p < 0.05, d = 0.28-1.00), while changes in these measures in the control groups were not significant (all p ≥ 0.05, d = -0.14-0.15). A series of repeated measures analyses of variance (ANOVA) indicated that (a) the maturity-related differences between jump training groups were observed only for reactive strength index, and (b) the improvements in all measures of neuromuscular performance were greater in jump training than in control group. This study demonstrated that important components of physical fitness in 12-14-year-old schoolboys may be acutely enhanced through a well-structured jump program and maturity seems to at least play a limited role in mediating these enhancements.

Elite status maintained: a 12-year physiological and performance follow-up of two Olympic champion rowers.

This case study reports the results of a 12-year (2005-2016) follow-up study of two Olympic champion rowers. The rowers were prospective athletes at the junior level when the study began, and we monitored their relevant physiological and performance data annually. Our findings indicated that their V̇O2max gradually increased up to about 22 years of age and leveled off at a value of approximately 7 l·min-1 with minimal fluctuations thereafter. However, the variables that directly influence the V̇O2max changed. There was an age-related decline in maximal heart rate of about 0.5 beats·year-1, while oxygen pulse, which serves as an indirect measure of stroke volume, correspondingly increased by about 1 ml O2·beat-1 per year, allowing the athletes to maintain exceptional V̇O2max values. Maximal minute power of the studied rowers, derived each year from their ramp-wise tests, closely resembled the mean power output sustained during the 2000-m all-out tests on a rowing ergometer. A 12-year improvement of 28% and 33% occurred for the mean power output sustained over 2000 and 6000-m on a rowing ergometer, respectively. The findings contribute to the body of knowledge on athletes representing the true elites of their respective sports.

Tapering Practices of Croatian Open-Class Powerlifting Champions.

Grgic, J and Mikulic, P. Tapering practices of Croatian open-class powerlifting champions. J Strength Cond Res 31(9): 2371-2378, 2017-The aim of this study was to explore tapering practices among 10 Croatian open-class powerlifting champions (mean ± SD: age 29.2 ± 3.2 years; Wilks coefficient 355.1 ± 54.8). The athletes were interviewed about their tapering practices using a semi-structured interview after which the audio content was transcribed. The athletes reported decreasing training volume during the taper by 50.5 ± 11.7% using a step type or an exponential type of taper with a fast decay. Training intensity was maintained or increased during the taper, and it reached its highest values 8 ± 3 days before the competition. Training frequency was reduced or maintained during the taper. The final week included a reduction in training frequency by 47.9 ± 17.5% with the last training session performed 3 ± 1 days before the competition. The participants typically stated that the main reasons for conducting the taper were maintaining strength and reducing the amount of fatigue. They also stated that (a) the taper was structured identically for the squat, bench press, and the deadlift; (b) the training during the taper was highly specific, the assistance exercises were removed, and the same equipment was used as during competition; (c) the source of information for tapering was their coach, and training fluctuated based on the coach's feedback; and (d) nutrition, foam rolling, static stretching, and massage were all given extra attention during the taper. These results may aid athletes and coaches in strength sports in terms of the optimization of tapering variables.

Peak Power Output Test on a Rowing Ergometer: A Methodological Study.

We aimed to examine the reliability and validity of the peak power output test on a rowing ergometer (Concept II Model D Inc.) and to establish the "optimal resistance" at which this peak power output was observed in 87 participants with varying levels of physical activity and rowing expertise: 15 male and 12 female physically inactive students (age: 21 ± 2 years), 16 male and 20 female physically active students (age: 23 ± 2 years), and 15 male and 9 female trained rowers (age: 19 ± 2 years). The participants performed countermovement jump (CMJ) test on a force plate, followed by 3 maximal-effort rowing trials using the lowest, medium, and the highest adjustable resistance settings (i.e., "1", "5," and "10" on the resistance control dial on the ergometer) in randomized order. The test proved to be reliable (coefficients of variation: 2.6-6.5%; intraclass correlation coefficients: 0.87-0.98). The correlation coefficients between CMJ peak power and rowing peak power (both in watts per kilogram) were fairly consistent across all 3 groups of participants and resistance levels, ranging between r = 0.70 and r = 0.78. Finally, the highest power output was observed at the highest resistance setting in 2 nonathletic groups (p < 0.01), whereas rowers seem to produce the highest power output at the moderate-resistance setting. We conclude that the power output test on a Concept II rowing ergometer may serve as a reliable and valid tool for assessing whole-body peak power output in untrained individuals and rowing athletes.

Bilateral synergies in foot force production tasks.

We analysed the effects of task symmetry during bilateral accurate force production tasks performed by the two feet. In particular, we tested a hypothesis that bilateral deficit would lead to higher indices of synergies defined as co-varied adjustments in the two forces across trials that reduced total force variability. The subjects produced steady-state force followed by a quick force pulse into the target. The two feet could be acting both into plantar flexion and into dorsiflexion (symmetrical tasks), or in opposite directions (asymmetrical task). We used the framework of the uncontrolled manifold hypothesis to quantify two variance components, one of which did not change total force (V UCM), while the other did (V ORT). Synergy indices during the asymmetrical task were higher than in either symmetrical task. The difference was due to higher V UCM (compared to the symmetrical plantar flexion task) or lower V ORT (compared to the symmetrical dorsiflexion task). The synergy index showed a drop (anticipatory synergy adjustment, ASA) starting 100-150 ms prior to the force pulse initiation. The ASA tended to be shorter and of a smaller magnitude for the asymmetrical task. This is the first demonstration of bilateral synergies during accurate force production by the legs. We conclude that bilateral deficit has no or weak effects on two-leg synergies. The results fit the earlier introduced scheme with two groups of neural variables defining average performance of a redundant system and patterns of co-variation among its elemental variables, respectively.

Validation of the Sensewear Armband during recreational in-line skating.

Multi-sensor body monitors that combine accelerometry with other physiological data are designed to overcome drawbacks of accelerometers in assessing activities with little or no vertical movement. One of such devices is the Sensewear Armband (SWA) which has been extensively validated during various activities. However, very few of the validation studies included activities other than walking and running. The aim of this investigation was to assess the validity of the SWA during recreational in-line skating. Nineteen participants (11 females and 8 males), 28 (±6) years of age, performed in-line skating exercise on a circular track at a self-selected pace. Energy expenditure was measured with the SWA and the Cosmed K4b(2) breath-by-breath portable metabolic unit. The mean (SD) energy expenditure during in-line skating estimated by the SWA [25.5 (5.8) kJ/min] was significantly lower compared with indirect calorimetry [44.2 (9.7) kJ/min, P < 0.001]. Similarly, the mean (SD) MET values recorded by the SWA were also lower compared with IC [5.3 (1.0) METs vs. 9.1 (1.6) METs, P < 0.001]. The ratio limits of agreement suggest that in 95% of cases the SWA will underestimate the energy expenditure and MET values during in-line skating by as much as 24-56% compared with indirect calorimetry. In conclusion, the results of the present study indicate that the SWA is not able to overcome the drawbacks of accelerometry in assessing activities with limited vertical movement.

Modeling longitudinal changes in maximal-intensity exercise performance in young male rowing athletes.

The purpose of the current study was to examine the effect of age and body size upon maximal-intensity exercise performance in young rowing athletes. Male participants (n = 171) aged 12-18 years were assessed using an "all-out" 30-s rowing ergometer test, and reassessed after 12 months. The highest rate of performance development, which amounts to [mean(SD)] +34%(23%) and +32%(23%) for mean and maximal power output, respectively, is observed between the ages of 12 and 13, while this rate of development gradually declines as the athletes mature through adolescence. Performance increases with body size, and mass, stature and chronological age all proved to be significant (all p < .05) explanatory variables of mean power output, with respective exponents [mean(SE)] of 0.56(0.08), 1.84(0.30) and 0.07(0.01), and of maximal power output, with respective exponents of 0.54(0.09), 1.76(0.32) and 0.06(0.01). These findings may help coaches better understand the progression of rowing performance during adolescence.

Ergogenic Effects of Sodium Bicarbonate Supplementation on Middle-, But Not Short-Distance Swimming Tests: A Meta-Analysis.

This meta-analysis explored the effects of sodium bicarbonate supplementation on swimming performance. Seven databases were searched to find relevant studies. A random-effects meta-analysis of standardized mean differences (SMD) was performed to analyze the data. Nine studies were included in the review. There was no significant difference between placebo and sodium bicarbonate when considering data from all included studies (SMD: -0.10; p = 0.208) or in the subgroup analysis for 91.4-m and 100-m swimming tests (SMD: 0.11; p = 0.261). In the subgroup analysis for 200-m and 400-m swimming tests, there was a significant ergogenic effect of sodium bicarbonate (SMD: -0.22; p < 0.001; -1.3%). Overall, these results suggest that sodium bicarbonate ingestion improves performance in 200-m and 400-m swimming events. The ergogenic effects of this supplement were small, but they may also be of substantial practical importance given that placings in swimming competitions are commonly determined by narrow margins.

Examining the Effects of Caffeine on Isokinetic Strength, Power, and Endurance.

This study examined caffeine's effects on isokinetic strength, power, and endurance. The sample included 25 young, resistance-trained males. The participants were tested on three occasions, in a control trial (no substance ingestion) and following the ingestion of 6 mg·kg-1 of caffeine or placebo. Exercise tests involved isokinetic knee extension and flexion using angular velocities of 60° s-1 and 180° s-1. Analyzed outcomes included peak torque, average power, and total work. For knee extension at an angular velocity of 60° s-1, there were significant differences for: (1) peak torque when comparing caffeine vs. control (Hedges' g = 0.22) and caffeine vs. placebo (g = 0.30) and (2) average power when comparing caffeine vs. control (g = 0.21) and caffeine vs. placebo (g = 0.29). For knee extension at an angular velocity of 180° s-1, there were significant differences for: (1) peak torque when comparing caffeine vs. placebo (g = 0.26), (2) average power when comparing caffeine vs. control (g = 0.36) and caffeine vs. placebo (g = 0.43), and (3) total work when comparing caffeine vs. control (g = 0.33) and caffeine vs. placebo (g = 0.36). Caffeine was not ergogenic for knee flexors in any of the analyzed outcomes. Additionally, there was no significant difference between control and placebo. In summary, caffeine enhances the mechanical output of the knee extensors at lower and higher angular velocities, and these effects are present when compared to placebo ingestion or no substance ingestion (control).

Negative Effects of Mental Fatigue on Performance in the Yo-Yo Test, Loughborough Soccer Passing and Shooting Tests: A Meta-Analysis.

We aimed to examine the effects of mental fatigue on the Yo-Yo test and Loughborough soccer passing and shooting tests performance using a meta-analysis. The search for studies was performed through eight bibliographic databases (Academic Search Elite, AUSPORT, Cochrane Library, PsycInfo, PubMed/MEDLINE, Scopus, SPORTDiscus, and Web of Science). The methodological quality of the included studies was assessed using the PEDro checklist. A random-effects meta-analysis was performed for data analysis. After reviewing 599 search results, seven studies with a total of ten groups were included in the review. All studies were classified as being of good methodological quality. Mental fatigue reduced the distance covered in the Yo-Yo test (Cohen's d: -0.49; 95% confidence interval [CI]: -0.66, -0.32). In the Loughborough soccer passing test, mental fatigue increased the original time needed to complete the test (Cohen's d: -0.24; 95% CI: -0.46, -0.03), increased penalty time (Cohen's d: -0.39; 95% CI: -0.46, -0.31), and decreased performance time (Cohen's d: -0.52; 95% CI: -0.80, -0.24). In the Loughborough soccer shooting test, mental fatigue decreased points per shot (Cohen's d: -0.37; 95% CI: -0.70, -0.04) and shot speed (Cohen's d: -0.35; 95% CI: -0.64, -0.06). Overall, the findings presented in this review demonstrated that mental fatigue negatively impacts endurance-based running performance as well as soccer passing and shooting skills.

Two aspects of feedforward postural control: anticipatory postural adjustments and anticipatory synergy adjustments.

We used the framework of the uncontrolled manifold hypothesis to explore the relations between anticipatory synergy adjustments (ASAs) and anticipatory postural adjustments (APAs) during feedforward control of vertical posture. ASAs represent a drop in the index of a multimuscle-mode synergy stabilizing the coordinate of the center of pressure in preparation to an action. ASAs reflect early changes of an index of covariation among variables reflecting muscle activation, whereas APAs reflect early changes in muscle activation levels averaged across trials. The assumed purpose of ASAs is to modify stability of performance variables, whereas the purpose of APAs is to change magnitudes of those variables. We hypothesized that ASAs would be seen before APAs and that this finding would be consistent with regard to the muscle-mode composition defined on the basis of different tasks and phases of action. Subjects performed a voluntary body sway task and a quick, bilateral shoulder flexion task under self-paced and reaction time conditions. Surface muscle activity of 12 leg and trunk muscles was analyzed to identify sets of 4 muscle modes for each task and for different phases within the shoulder flexion task. Variance components in the muscle-mode space and indexes of multimuscle-mode synergy stabilizing shift of the center of pressure were computed. ASAs were seen ∼ 100-150 ms prior to the task initiation, before APAs. The results were consistent with respect to different sets of muscle modes defined over the two tasks and different shoulder flexion phases. We conclude that the preparation for a self-triggered postural perturbation is associated with two types of anticipatory adjustments, ASAs and APAs. They reflect different feedforward processes within the hypothetical hierarchical control scheme, resulting in changes in patterns of covariation of elemental variables and in their patterns averaged across trials, respectively. The results show that synergies quantified using dissimilar sets of muscle modes show similar feedforward changes in preparation to action.

Maturation to elite status: a six-year physiological case study of a world champion rowing crew.

This case study reports the results of a 6-year (2005-2010) follow-up study of a world-class rowing crew, the current world champions. The rowers were 15-16 years old and prospective competitors at the junior level when the study began in 2005, and we monitored their physical, physiological, and rowing ergometer performance data annually. Our findings indicated that over the 6-year period gains in stature, averaged across rowers, amounted to only +2 cm (+1%). In contrast, body mass increased by +9 kg (+10%) and fat-free mass by +11 kg (+15%). A significant linear trend (R (2) = 0.998, P < 0.001) and a +26% increase in maximal oxygen uptake (in L min(-1)) was evident from 2005 to 2009, resulting in a leveling-off and a crew average of ~6.6 L min(-1) (~70 mL kg(-1) min(-1)) during the last 2 years of assessment. Power output at anaerobic threshold increased by +23%, subsequently amounting to a crew average of 359 W in 2010. Oxygen uptake at anaerobic threshold, expressed as a percentage of maximal oxygen uptake, changed little and ranged between 82 and 85%. A curvilinear regression provided the best fit to describe the 6-year improvement (+7%) in 2000 m (R (2) = 0.984, P < 0.001) and 6000 m (R (2) = 0.989, P < 0.001) rowing ergometer performance times. Performance-related physical and physiological parameters seem to level-off at about 20 years of age, which may partly explain the corresponding stabilization in ergometer performance times over the last years of assessment.

Discriminative ability of the Yo-Yo intermittent recovery test (level 1) in prospective young soccer players.

We evaluated the sensitivity of the Yo-Yo intermittent recovery test-level 1 (Yo-Yo IR1) when discriminating among players in varying playing positions and different age categories in youth soccer. One-hundred and six prospective young soccer players, grouped on the basis of chronological age (under-13, under-14, under-15, under-16, under-17, under-18, and under-19) and playing position (center-backs, fullbacks, center midfielders, wide midfielders, and forwards), participated in the study. The players were administered a single Yo-Yo IR1 test at the beginning of the spring season. Analysis of variance revealed significant (F = 25.3; p < 0.001) group differences in Yo-Yo IR1 test performance scores among the observed age categories, and a systematic age-related increase in the Yo-Yo IR1 test performance was evident. Subsequent post hoc comparisons identified a number of significant differences among the selected age categories in Yo-Yo IR1 test performance. Analysis of covariance identified significant differences among playing positions (F = 3.1; p < 0.019) in the Yo-Yo IR1 test performance after controlling for age (F = 135.1; p < 0.001). Subsequent pairwise comparisons of the adjusted Yo-Yo IR1 test performance identified that center-backs had achieved significantly lower (all p < 0.01) performance scores than center midfielders, wide midfielders, and forwards, but not fullbacks. These results could be of practical value to coaches and scientists for further development of talent selection and profiling procedures in soccer, particularly because (a) the endurance performance represents a very important fitness component in selection and profiling of young soccer players and (b) the Yo-Yo IR1 test proved to be valid, reliable, and easily available measurement tool of a player's soccer-specific endurance capacity.

Strong relationship between heart rate deflection point and ventilatory threshold in trained rowers.

The purpose of this study was to assess the relationship between heart rate deflection point (HRDP) and ventilatory threshold (VT) to the physiological and performance variables in a relatively large group of trained men rowers. We proposed the hypothesis that physiological and performance variables corresponding to HRDP are not significantly different from corresponding variables at VT, which would justify the use of HRDP as a simple, affordable, and noninvasive method of anaerobic threshold assessment in trained rowers. Eighty-nine trained men rowers (mean ± SD: age 21.2 ± 4.1 years; stature 1.89 ± 0.06 m; body mass 89.2 ± 8.4 kg; VO2max [maximum oxygen uptake] 5.39 ± 0.62 L/min⁻¹) completed an incremental rowing ergometer exercise test to exhaustion. Three independent, experienced observers determined both HRDP and VT. HRDP was determined by visual and computer-aided regression analyses and was evident in all rowers. The main findings include (a) there is a strong relationship among all observed physiological and performance variables corresponding to HR(HRDP) and HR(VT) (r = 0.79-0.96; p < 0.001) and (b) power output, oxygen uptake, ventilation, tidal volume and breathing rate corresponding to HR(HRDP) and HR(VT) were not significantly different (p ≥ 0.011), whereas HR(HRDP) was slightly but significantly higher than HR(VT) (174.5 vs. 172.8 beats·min⁻¹; p = 0.003). The standard error of the estimate in predicting the HR(VT) based on HR(HRDP) was 5.1 beats·min⁻¹. The subsequent data suggest that, in general, trained rowers may be able to periodically assess their aerobic endurance and evaluate the effects of training programs using the HRDP method.

Acute effects of caffeine supplementation on resistance exercise, jumping, and Wingate performance: no influence of habitual caffeine intake.

This study explored the influence of habitual caffeine intake on the acute effects of caffeine ingestion on resistance exercise, jumping, and Wingate performance. Resistance-trained males were tested following the ingestion of caffeine (3 mg/kg) and placebo (3 mg/kg of dextrose). Participants were classified as low caffeine users (n = 13; habitual caffeine intake: 65 ± 46 mg/day) and as moderate-to-high caffeine users (n = 11; habitual caffeine intake: 235 ± 82 mg/day). Exercise performance was evaluated by measuring: (a) movement velocity, power, and muscular endurance in the bench press; (b) countermovement jump; and, (c) a Wingate test, performed in that order. Two-way repeated-measures ANOVA revealed a significant main effect (p < 0.05) for condition in the majority of analyzed exercise outcomes. In all cases, effect sizes for condition favoured caffeine and ranged from 0.14 to 0.97. Mean increases in velocity and power in resistance exercise ranged from 0.02 to 0.08 m/s and 42 to 156 W, respectively. The number of performed repetitions increased by 1.2 and jump height by 0.9 cm. Increases in power in the Wingate test ranged from 31 to 75 W. We did not find significant group × condition interaction effect (p > 0.05) in any of the analyzed exercise outcomes. Additionally, there were no significant correlations (p > 0.05; r ranged from -0.29 to 0.32) between habitual caffeine intake and the absolute change in exercise performance. These results suggest that habitual caffeine intake might not moderate the ergogenic effects of acute caffeine supplementation on resistance exercise, jumping, and Wingate performance.

Effects of Paracetamol (Acetaminophen) Ingestion on Endurance Performance: A Systematic Review and Meta-Analysis.

Several studies explored the effects of paracetamol (acetaminophen) ingestion on endurance performance, but their findings are conflicting. Therefore, this review aimed to conduct a meta-analysis examining the effects of paracetamol ingestion on endurance performance. Five databases were searched to find relevant studies. The PEDro checklist was used to assess the methodological quality of the included studies. Data reported in the included studies were pooled in a random-effects meta-analysis. A total of ten studies with good or excellent methodological quality were included in the meta-analysis (pooled n = 141). All included studies had a randomized, double-blind, crossover design. In the main meta-analysis, there was no significant difference between the effects of placebo and paracetamol on endurance performance (Cohen's d = 0.09; 95% confidence interval (CI): -0.04, 0.22; p = 0.172). However, an ergogenic effect was found when we considered only the studies that provided paracetamol 45 to 60 min before exercise (Cohen's d = 0.14; 95% CI: 0.07, 0.21; p < 0.001). In a subgroup analysis that focused on time-to-exhaustion tests, there was a significant ergogenic effect of paracetamol ingestion (Cohen's d = 0.19; 95% CI: 0.06, 0.33; p = 0.006). There was no significant difference between placebo and paracetamol in a subgroup analysis that focused on time trial tests (Cohen's d = 0.05; 95% CI: -0.12, 0.21; p = 0.561). In conclusion, paracetamol ingestion appears to enhance performance (a) in time-to-exhaustion endurance tests and (b) when consumed 45 to 60 min before exercise.