PURPOSE:Given the growing evidence of the importance of durability in endurance performance, this study aimed to investigate the reliability of a triathlon-specific test protocol for assessing physiological determinants of fatigued running performance, that is, after strenuous cycling in well-trained triathletes of both sexes. METHODS:On 2 occasions, 10 triathletes (5 females; maximal oxygen uptake [V˙O2peak] 60.4 [6.0] mL·min-1·kg-1) completed an incremental cycling test (∼2 W·kg-1, +20 W, 3 min) to exhaustion followed by a constant-workload segment at 85% of power at lactate threshold 2 (LT2) to reach 20 kJ·kg-1 (males) or 15 kJ·kg-1 (females) of total mechanical work. Subsequently, they performed an incremental running test to exhaustion (2.8 m·s-1, +0.4 m·s-1, 5 min + 30-s rest) to assess fatigued V˙O2peak, oxygen cost, and lactate thresholds. Energy expenditure and carbohydrate/fat oxidation were calculated during all submaximal work rates. RESULTS:All diagnostic determinants of fatigued running performance showed good to excellent reliability (intraclass correlation coefficient [ICC] ≥ .845), except for fractional utilization of V˙O2peak at LT2 (ICC = .193), along with small measurement errors (typical error ≤ 3.6%) for all determinants. In contrast to the excellent reliability of energy expenditure during constant-workload cycling (ICC = .940, typical error = 3.4%), substrate oxidation demonstrated limited reliability during constant cycling and submaximal fatigued running (ICC = .560-.928, typical error = 6.3%-19.6%). CONCLUSION:The triathlon-specific test protocol demonstrated high reliability for measures of fatigued running performance, comparable to fresh measurements in previous reliability studies, making it suitable for regular evaluation of triathletes.

Current models of the power-duration relationship often focus on limited time domains. This study aims to develop and validate a Multi-Domain Power-Duration model (MuDo-PD) to predict power outputs across a wide range of exercise duration (up to 60 min) in cycling, using peak power output (PPO), maximal aerobic power (MAP), and power at lactate threshold 2 (PLT2). Thirty-three well-trained male cyclists (29.2 ± 9.7 yrs; V̇O₂max: 67.2 ± 5.1 mL·min⁻¹·kg⁻¹) performed lab tests to determine PPO (15-s sprint), MAP (ramp test), and PLT2, and completed time trials from 30 to 3600 s. Based on the resulting power-duration profiles and three anchor points (PPO, MAP, PLT2), individual exponential time decay constants (k) were calculated for short (1–300 s; Anaerobic Power Reserve, kAnPR) and long durations (300–3600 s; Aerobic Power Reserve, kAePR), forming the basis of the MuDo-PD model. Internal validation was performed within the modeling cohort by comparing the MuDo-PD to an established critical power approach (OmPD). External validation involved predicting the target power output during a time-to-exhaustion trial in an independent sample of 75 well-trained athletes. Decay constants were kAnPR = -0.023 ± 0.003 s− 1 and kAePR = -0.0023 ± 0.0008 s− 1. The MuDo-PD model showed moderate to excellent agreement with actual power (ICC = 0.63–0.95; RSE = 29 ± 9 W), comparable to OmPD (ICC = 0.80–0.98, RSE = 19 ± 7 W). External validation confirmed excellent accuracy of MuDo-PD (ICC = 0.988; bias = 0.01 ± 17.8 W). The MuDo-PD model enables performance prediction across intensity domains up to 60 min using laboratory diagnostic parameters, offering a practical tool for performance assessment and training control.

OBJECTIVES:While reliable performance diagnostics are crucial for guiding training and detecting small changes in swimming performance, the reliability of existing protocols remains insufficiently evaluated. DESIGN:Test-retest study. METHODS:Twenty-four swimmers and triathletes of both sexes completed a 20-s sprint to assess anaerobic power (i.e., maximal lactate accumulation rate [ċLamax], peak lactate concentration [Lapeak]) and a 3-min step test (ST) to evaluate aerobic performance indicators (i.e., post-exercise peak oxygen uptake [V̇O2peak], cost of swimming [Cs], speed at lactate thresholds [vLT1, vLT2] and in the final step [vpeak], alongside corresponding heart rate [HR]) on three separate days (within 3 weeks). Reliability and agreement were examined using (among others) intraclass correlation coefficient (ICC 2,1), typical error (TE), and TE to smallest worthwhile change (SWC) ratio, indicating sensitivity. RESULTS:The sprint demonstrated moderate reliability for ċLamax (ICC: 0.625-0.728) and Lapeak (ICC: 0.705-0.749), with high TEs of 11.8-16.8% and 9.7-12.0%, respectively. Although familiarization improved reliability, sensitivity remained inadequate (TE/SWC: ≥1.23). The ST exhibited good to excellent reliability (mixed sensitivity) across all parameters. Uncorrected post-exercise V̇O2peak (ICC: 0.829-0.963, TE: 3.8-7.1%, TE/SWC: 1.02-1.83) and Cs (ICC: 0.884-0.952, TE: 3.8-5.7%, TE/SWC: 0.83-1.17) aligned with HR-corrected values. vLT1, vLT2, and vpeak showed excellent reliability (ICC: 0.971-0.990, TE: 0.8-1.4%) with adequate sensitivity (TE/SWC: 0.60-1.14), whereas HR measures were less reliable (ICC: 0.828-0.951, TE: 1.2-3.5%) and insufficiently sensitive (TE/SWC ≥ 1.60). CONCLUSIONS:The ST provides a reliable method for assessing aerobic performance, with high sensitivity for lactate-based training intensity markers and Cs, but limited sensitivity for V̇O2peak and HR. The 20-s sprint requires methodological refinement before practical application.

This study investigated (1) the agreement of modeled lactate threshold 2 using peak oxygen uptake, cost of locomotion, and fractional utilization of peak oxygen uptake at lactate threshold 2 with the maximal lactate steady state in running and cycling; (2) the impact of different cost of locomotion determination methods on the accuracy of the model and (3) the contributions of peak oxygen uptake, cost of locomotion, and fractional utilization of peak oxygen uptake at lactate threshold 2 to the work rate at maximal lactate steady state. Thirty-four endurance-trained athletes (27.7±6.9 y, 56.2±5.5 ml∙kg-1∙min-1) completed an incremental step test on a treadmill or a cycling ergometer. Peak oxygen uptake, cost of locomotion at lactate threshold 1, at 80% of peak oxygen uptake, and at lactate threshold 2, and fractional utilization of peak oxygen uptake at lactate threshold 2 were assessed. Two to five 30-minute constant work rate tests were performed for maximal lactate steady state determination. Moderate to good agreement was found between modeled work rate corresponding to lactate threshold 2 and the maximal lactate steady state for running and cycling (intraclass correlation coefficient≥0.698) with the smallest mean difference (±limits of agreement) for cost of locomotion determined at lactate threshold 2 with -2.0±5.2 and -0.9±6.0%, respectively. Overall, 83 and 79% of the variance in the maximal lactate steady state was explained by peak oxygen uptake, cost of locomotion determined at lactate threshold 2, and fractional utilization of peak oxygen uptake at lactate threshold 2, respectively. Peak oxygen uptake and cost of locomotion determined at lactate threshold 2 contributed the most to the regression R 2 in running (54 and 40%) and cycling (74 and 51%), while fractional utilization of peak oxygen uptake at lactate threshold 2 had the smallest contribution (4 and 5%). Based on the high accuracy of the model with the major contribution of peak oxygen uptake and cost of locomotion determined at lactate threshold 2, the work rate corresponding to the maximal lactate steady state could be improved focusing on these two variables during training.

High‐velocity eccentric training elicits exercise‐induced muscle damage ( EIMD ), predominantly attributed to mechanical strain. However, the potential contribution of metabolic stress to muscle damage remains underexplored, especially in trained populations. This study examined whether metabolic changes contribute to EIMD during maximal eccentric hamstring curls. Thirty male participants performed five sets of 15 maximal eccentric leg curls at 210°/s. Muscle oxygenation (SmO₂) and pulmonary gas exchange (VO 2 and VCO₂) were recorded during the intervention. Creatine kinase (CK), muscle soreness, muscle stiffness, muscle contractility, peak torque, and maximal voluntary contraction (MVC) were measured pre‐exercise, post, and over 96 h of recovery. Linear mixed models were used to analyze associations between metabolic parameters and damage markers. Peak torque declined significantly after 48 h (−25.64%), muscle stiffness was increased post ( p = 0.004); CK peaked at 96 h ( p < 0.001). For peak torque and CK, linear mixed models were fitted revealing significant contributions of △VO 2 % ( p = 0.04) and △VCO 2 % ( p = 0.08) to peak torque. Fixed effects explained 30.6% of the variance. Higher oxygen uptake (△VO 2 rec%) during rest intervals predicted lower CK elevations ( p = 0.04). SmO₂ decreased by 13% within sets but had no significant effects on EIMD. Our findings indicate metabolic factors significantly contribute to EIMD in high‐velocity eccentric protocols. Greater aerobic demands within sets were associated with greater force deficits, whereas greater oxygen uptake during rest mitigated creatine kinase levels. Enhancing aerobic capacity and fatigue resistance could mitigate muscle damage and improve recovery trajectories in similarly demanding training contexts.

Abstract The study investigated associations of metabolic, anthropometric, and neuromuscular parameters with 50 to 400 m front crawl performance. Competition performances of 24 female swimmers (14.9 ± 1.3 years) were recorded and metabolic determinants (maximal oxygen uptake and lactate accumulation [ċLamax], cost of swimming [C], and lactate threshold 1 [LT1] using 200 m all-out, 20 s sprint, 500 m submaximal, and 3 min incremental test, respectively), anthropometry and dryland strength (squat and bench press 1 repetition maximum [1RMSQ/1RMBP] and mean propulsive power [MPPSQ/MPPBP]) were assessed. 1RMSQ (61.9 ± 13.3 kg) and MPPBP (207 ± 45 W) correlated significantly with 50 (1.84 ± 0.07 m∙s−1) and 100 m performance (1.68 ± 0.06 m∙s−1) (r ≥ 0.45) and ċLamax (0.35 ± 0.12 mmol·L−1·s−1) and body mass (60.1 ± 7.0 kg) with 50 and 100 m, respectively (r ≥ 0.44). Only LT1 (1.23 ± 0.04 m∙s−1) correlated significantly with 200 (1.52 ± 0.05 m∙s−1) and 400 m performance (1.43 ± 0.06 m∙s−1) (r ≥ 0.56). Multiple regression explained 33–35% and 61–86% of the variance in short- and middle-distance performance based on 1RMSQ and arm span and LT1, C, and fat percentage, respectively. Based on the analyses, mechanical determinants are more predictive of short- and metabolic determinants of middle-distance performance.

Despite growing interest in blood flow restriction (BFR) for enhancing training adaptations, its acute impacts on local and systemic physiological stress remain incompletely understood. This study compared the metabolic and perceptual responses of low-intensity cycling (LI) with BFR (LI + BFR) to both LI and high-intensity (HI) cycling without BFR, matched for time and external work. Ten males (26.9 ± 4.6 years) completed LI (20 min at 55% peak aerobic power output, PPO), LI + BFR (with 50% limb occlusion pressure), and HI (10 × 1 min at 90% PPO interspersed with 1-min recovery at 20% PPO) protocols in a randomized cross-over design. Interstitial metabolic responses were assessed via microdialysis in the vastus lateralis; systemic blood responses were evaluated via venous blood gas analysis. Cardiorespiratory responses, including heart rate, oxygen uptake, and ventilation, were continuously monitored during exercise. Serum creatine kinase (CK) and lactate dehydrogenase (LDH) were measured as indirect markers of muscle damage, and perceptual responses were documented. Muscle interstitial lactate and pyruvate were highest in HI, followed by LI + BFR, and lowest in LI (p < 0.05). Systemic blood and cardiorespiratory responses were comparable between LI + BFR and HI and exceeded LI (p < 0.05), while electrolyte shifts occurred across all conditions (p < 0.001) without between-condition differences. All protocols increased CK and LDH 24-48 h post-exercise, with the greatest increases in HI (p < 0.05). Perceived exertion and pain were higher in LI + BFR than in other conditions (p < 0.05). In conclusion, BFR intensifies local and systemic stress during LI and may be a potent strategy to promote muscle adaptive stimulus. However, when time and total external work are matched, high mechanical loading appears more effective in inducing local stress, which may be essential for further muscular adaptation processes.

The study investigated 1.The agreement of modeled lactate threshold 2 (modLT2) using maximal oxygen uptake (V̇O2peak),cost of locomotion (C), and fractional utilization of (V̇O2peak) at LT2 (LT2%) with maximal lactate steady state (MLSS) in running and cycling. 2.The impact of different C determination methods on the accuracy of the model. 3.The contributions of V̇O2peak,C, and LT2% to work rate at MLSS. Thirty-four endurance-trained athletes (27.7±6.9 yrs, 56.2±5.5 ml∙kg-1∙min-1) completed an incremental step test on a treadmill or cycling ergometer.V̇O2peak,C at lactate threshold 1, 80% of V̇O2peak and LT2 (CLT2), and LT2% were assessed.Two to five 30 min constant work rate tests were performed for MLSS determination. Moderate to good agreement was found between modLT2 and MLSS for running and cycling (ICC ≥ 0.698) with the smallest mean difference (± limits of agreement) for CLT2 with -2.0±5.2% and -0.9±6.0%, respectively.83% and 79% of the total variance of MLSS was explained by V̇O2peak,CLT2 and LT2%, respectively.V̇O2peak and CLT2 contributed the most to the regression R2 in running (54% and 40%) and cycling (74% and 51%), while LT2% had the smallest contribution (4% and 5%). Based on the high accuracy of the model with the major contribution of V̇O2peak and CLT2, MLSS could be improved focusing on these two variables during training.

Low-load resistance training with blood flow restriction (BFR) has gained popularity for eliciting muscular adaptations comparable to high-load resistance training. However, its acute metabolic and electrolyte responses within the exercising limb, particularly under exhaustive conditions, remain insufficiently characterized. This study aimed to assess these responses using simultaneous arterial and venous blood sampling during unilateral elbow flexion to volitional failure under three conditions: low-load (LL-RT, 30

Strength training responses are influenced by sets, repetitions, and mechanical load, whereas Blood Flow Restriction (BFR) training adds the variable of temporarily restricting blood flow via a tourniquet. This has intensified scientific discussions regarding the vascular responses and thereby safety of the BFR method. To address these concerns, we investigated intravascular pressure changes during low-load (LL-RT), low-load with BFR (LL-BFR-RT), and high-load (HL-RT) exercise. Ten healthy men (26.8 ± 4.59 years) performed unilateral biceps curls to failure in a randomized cross-over design: (1) LL-RT (30% 1RM), (2) LL-BFR-RT (30% 1RM, 50% LOP), and (3) HL-RT (75% 1RM). Total workload was significantly higher in LL-RT (692 ± 251 kg) compared to LL-BFR-RT (378 ± 58.7 kg) and HL-RT (327 ± 65.1 kg, p < 0.001). In terms of mean values, LL-BFR-RT resulted in higher diastolic and mean arterial pressures during rest periods between sets compared to other conditions (p ≤ 0.02). Both LL-RT and LL-BFR-RT led to longer durations spent at increased diastolic (above 90 mmHg, LL-RT: ~419 s vs. LL-BFR-RT: ~356 s vs. Hl-RT: ~122 s), systolic (above 140 mmHg, LL-RT: ~437 s vs. LL-BFR-RT: ~336 s vs. HL-RT: ~199 s), and mean arterial pressures (above 107 mmHg, LL-RT: ~451 s vs. LL-BFR-RT: ~384 s vs. HL-RT: ~168 s) compared to HL-RT (p ≤ 0.028). Relative to total exercise time, LL-BFR-RT resulted in higher proportion of time spent at elevated diastolic (above 90 mmHg, LL-RT: ~56.5% vs. LL-BFR-RT: ~68.7% vs. Hl-RT: ~33.5%) and mean arterial pressures (above 107 mmHg, LL-RT: ~60.8% vs. LL-BFR-RT: ~74.0% vs. HL-RT: ~45.7%) compared to HL-RT (p ≤ 0.034). Peripheral venous pressure was significantly higher in LL-BFR-RT compared to other conditions (p < 0.001), with both absolute and relative time spent at higher pressures (above 75 mmHg, LL-RT: ~57.0 s and ~ 9.12% vs. LL-BFR-RT: ~424 s and ~ 81.7% vs. HL-RT: ~36.0 s and ~ 8.99%, p ≤ 0.002). Our results suggest that BFR training performed to failure imposes greater arterial and venous stress in the exercising limb compared to high-load training without BFR, particularly due to prolonged exposure to elevated pressures. Further research is needed to assess the potential risks of elevated local arterial and venous pressure responses by frequent BFR use, particularly in populations with pre-existing medical conditions.

Understanding physiological determinants of lactate threshold 2 (LT2) is crucial for tracking adaptations and deriving individualized training recommendations in cycling. Therefore, the study investigated: 1. the accuracy of modeling power output at LT2 in young athletes of both sexes using maximal oxygen uptake ( V̇O_2_peak ), fractional utilization of V̇O_2_peak ( V̇O_2_peak ), and oxygen cost of cycling (Cc); 2. the influence of Cc determination on the model accuracy; 3. the influence of the model predictors and inclusion of maximal lactate accumulation rate ( ċLa_max ) on power at LT2 depending on sex. Eighty-three cyclists and triathletes (22 females, 61 males; age [median and IQR]: 14.6 [13.8–17.6] years, V̇O_2_peak [mean ± SD]: 59.2 ± 6.5 mL⋅kg–1⋅min–1) performed an incremental test to determine power at LT2, V̇O_2_peak, V̇O_2_peak at LT2, and Cc (assessed at 3 W⋅kg–1, 75 V̇O_2_peak, and 90 ≥ 0.961), with Cc at 90 ≥ 0.986). The three physiological determinants explained ≥ 98 V̇O_2_peak (62 and 67 R^2 ), followed by Cc (8 and 34 V̇O_2_peak at LT2 (5 and 12 ċLa_max did not improve the regression. V̇O_2_peak, V̇O_2_peak at LT2 and Cc accurately predict power at LT2 in young cycling athletes independent of sex, with determination of Cc at 90 V̇O_2_peak contributes most to LT2 in both sexes, Cc appears more important in young females.

PURPOSE:Maximal neuromuscular performance is a critical determinant of track sprint-cycling performance. This study investigated the relationships between force-velocity (F-v) and power-velocity (P-v) profiles derived from 5 strength exercises and maximal cycling performance in both seated and standing sprint positions. METHODS:Twenty-three elite track sprint cyclists (7 female, 16 male; flying 200 m: 9.5-11.5 s) participated in progressive loading tests involving back squat (BS), front squat, power clean (PC), leg press, and deadlift, in addition to maximal seated and standing acceleration sprints on a velodrome. F-v and P-v profiles were established using linear and nonlinear regression models to calculate maximal force (Fmax), maximal power output (Pmax), and maximal movement velocity (vmax) for each task performed. RESULTS:Significant positive correlations were observed between Fmax and Pmax across all strength exercises and cycling positions (r = .656-.914, P < .05). Partial correlations highlighted Fmax in the BS, front squat, and deadlift and Pmax in the PC and leg press as primary contributors, corresponding to intersection points of exercise- and cycling-specific F-v profiles. Multiple-regression analysis identified BS Fmax and PC Pmax as the strongest predictors of cycling Fmax and Pmax (R2 = .694-.964, P ≤ .001). Conversely, vmax was not significantly associated with any cycling performance variables. CONCLUSION:Strength exercises that replicate the kinematic patterns and F-v demands of sprint cycling, particularly BS and PC, are strongly associated with cycling-specific F-v and P-v characteristics, emphasizing that such exercises may enhance the transfer of strength gains to on-bike sprint performance. However, intervention studies are required to confirm causality.

Purpose : This study aimed to investigate oxygen/energy cost (OC/EC) of running and substrate utilization before and after strenuous cycling in well-trained junior triathletes and the relevance of changes in these variables for fatigued running performance. Methods : Nineteen junior squad triathletes (4 female, 15 male; 17.2 [1.8] y; maximal oxygen uptake ( ) 61.4 [5.1] mL·kg −1 ·min −1 ) completed 3 submaximal running steps (2.8 m·s −1 , +0.4 m·s −1 , and 5 min) under fresh conditions, followed by an incremental cycling test (∼2 W·kg −1 , +20 W, and 3 min) to exhaustion. Afterward, they performed another incremental running test to exhaustion under fatigued conditions for , OC, and time-to-exhaustion assessment. During both runs, OC, EC, and carbohydrate/fat oxidation (CHO/FO) were assessed. Results : Contrary to trivial/small average changes in OC (210 [15] to 209 [14] mL·kg −1 ·km −1 , P = .71) and EC (4.75 [0.33] to 4.59 [0.29] kJ·kg −1 ·km −1 , P = .02), CHO decreased (2.96 [0.68] to 2.08 [0.68] g·min −1 ) while FO increased (0.15 [0.13] to 0.48 [0.22] g·min −1 ) significantly from fresh to fatigued running ( P < .001). Besides ( r = .68, P = .002), the changes in CHO ( r = –.60, P = .01) and FO ( r = .67, P = .003) were significantly correlated with fatigued time to exhaustion (1715 [172] s). Multiple regression and commonality analysis identified , OC, and the change in FO as the best model for time to exhaustion ( R 2 = 88%). Conclusion : Despite trivial/small changes in OC/EC from fresh to fatigued running, a pronounced shift in substrate utilization from CHO to FO was evident in junior triathletes, which was also associated with fatigued running performance.

Blood flow restriction (BFR) training has been shown to induce exercise-induced muscle damage (EIMD) in some cases, although findings are inconsistent and the influence of the applied arterial occlusion pressure (AOP) remains unclear. This single-blind, randomized controlled trial investigated the effects of different percentages of AOP on EIMD and acute physiological responses in 40 participants allocated to four groups: no pressure (NP), low pressure (LP; 50% AOP), medium pressure (MP; 75% AOP), and high pressure (HP; 100% AOP). Participants performed unilateral knee extensions at 30% of their one-repetition maximum up to four sets of 20 repetitions or until failure. EIMD was primarily assessed by the changes in isokinetic peak torque 24 h, 48 h and 72 h post-exercise (Δ to baseline). Secondary markers included perceived pain, blood biomarkers (creatine kinase, myoglobin) and muscle swelling. Additionally, acute physiological responses were assessed, including continuous measurement of muscle oxygen saturation (SmO2) during exercise, perceived exertion (RPE) immediately after the exercise bout, and blood lactate concentration measured at 1, 3, 7, and 10 min post-exercise. NP showed greater strength loss at 24 h post-exercise compared to MP (MD = − 9.95, p = .042, 95% CI [− 19.7, − 0.19]) and HP (MD = − 10.51, p = .034, 95% CI [− 20.52, − 0.49]). Pain ratings were higher in NP compared to MP (p = .001) and HP (p = .003) at 24 h post, and remained elevated at 48 h compared to MP (p = .003) and HP (p = .047). NP and LP completed more repetitions than MP and HP. HP exhibited a greater reduction in SmO2compared to NP. Perceived exertion was higher in MP and HP. LP showed higher average lactate concentrations than NP (p = .020). CK and MB responses showed no time-specific group differences. These findings suggest that BFR training, even at higher pressures, does not increase EIMD compared to free-flow exercise, and that MP and HP may even attenuate strength loss and pain following exercise.

ABSTRACTLow‐load blood‐flow‐restriction resistance training (LL‐BFR‐RT) is gaining popularity, but its physiological effects remain unclear. This study aimed to compare LL‐BFR‐RT with low‐load resistance exercise (LL‐RT) and high‐load resistance exercise (HL‐RT) on metabolism, electrolytes, and ions in the lower extremities by invasive catheter measurements, which are crucial for risk assessment. Ten healthy men (27.6 ± 6.4 years) completed three trials of knee‐extensor exercises with LL‐RT (30% 1RM), LL‐BFR‐RT (30% 1RM, 50% limb occlusion pressure), and HL‐RT (75% 1RM). The exercise protocol consisted of four sets to voluntary muscle failure with 1 min of rest between sets. Blood gas analysis was collected before, during, and after each trial through intravenous catheters at the exercising leg. LL‐BFR‐RT had lower total workload (1274 ± 237 kg, mean ± SD) compared to LL‐RT (1745 ± 604 kg), and HL‐RT (1847 ± 367 kg, p < 0.01), with no difference between LL‐RT and HL‐RT. Pain perception did not differ significantly. Exercise‐induced drop in oxygen partial pressure, lactate accumulation and electrolyte shifts (with increased [K+]) occurred during under all conditions (p < 0.001). Creatine kinase and lactate dehydrogenase increased significantly 24‐ and 48‐h postexercise under all three conditions (p < 0.001). This study, using invasive catheter measurements, found no significant differences in metabolic, ionic, and electrolyte responses among LL‐BFR‐RT, LL‐RT, and HL‐RT when exercised to voluntary muscular failure. LL‐BFR‐RT reduced time to failure without specific physiological responses.

The aim of this study was to investigate the effect of 300 intermittent countermovement jumps (CMJs) on the mechanical power distribution at the joints of the lower limbs and the influence of the upper body to explain vertical jump performance. Fifteen male sport students (age 24.5 ± 2.3 years; body height 1.85 ± 0.06 m; body mass 84.8 ± 8.5 kg) performed a set of intermittent 300 CMJs at maximal effort. An inverse-dynamic approach was used to calculate the mechanical power at the hip, knee, and ankle joint for each jump. Jump height and mechanical power in the knee and ankle joints decreased significantly (p < .010), while remained the same in the hip joint. In contrast, a significant increased vertical velocity was observed for the upper body segment. In addition, a significant higher angular momentum at the center of mass was detected during the braking and propulsion phase. The findings highlight a fatigue-related decrease in lower limb power, particularly in the knee and ankle joints, which changed the mechanical power distribution at the joints of the lower limbs. The trunk extensor muscles were probably able to counteract the fatigue-related decrease in lower limb power by increased vertical velocity of the upper body segment and higher angular momentum at the center of mass during the braking and propulsion phase. Accordingly, the most effective way to maintain jumping performance in fatigued state would be to improve the fatigue resistance of the knee extensors, ankle plantar flexors, and trunk extensor muscles.

The study estimated lower and upper extremity contributions to whole-body front crawl swimming using semi-tethered load-velocity profiling. Nine female and 11 male (inter)national-level swimmers performed 20 m semi-tethered sprints, each with five progressive loads for lower (leg kicking), upper (arm stroke), and whole-body front crawl movements. The theoretical maximal speed (v0) and load (L0), and active drag (Da) were expressed as a percentage of the sum of both extremities for the movements of each extremity to calculate their contributions. The difference of whole-body values minus the sum of both extremities was used to estimate whole-body reserves. Lower (upper) body contributions were 43.8 ± 2.8% (56.2%) for v0, 37.3 ± 7.1% (62.7%) for L0, and 39.6 ± 5.6% (60.4%) for Da. Statistically significant whole-body reserves were found for v0 (-30.9 ± 3.9%, p < 0.001) and Da (-5.7 ± 11.7%, p = 0.04). V0 reserves correlated very highly with whole-body v0 in males (r = 0.71, p = 0.014) and moderately in females (r = 0.47, p = 0.21). The lower extremities contribute substantially to front crawl load-velocity profiles of highly trained swimmers. Higher sprint swimming speeds are associated with an efficient speed transfer from lower- and upper- to whole-body movement.

PURPOSE:The study examined the longitudinal interplay of anthropometric, metabolic, and neuromuscular development related to performance in adolescent national-level swimmers over 12 months.METHODS:Seven male and 12 female swimmers (14.8 [1.3] y, FINA [International Swimming Federation] points 716 [51]) were tested before (T0) and after the preparation period (T1), at the season's peak (T2), and before the next season (T3). Anthropometric (eg, fat percentage) and neuromuscular parameters (squat and bench-press load-velocity profile) were assessed on dry land. Metabolic (cost of swimming [C], maximal oxygen uptake [V˙O2peak], and peak blood lactate [bLapeak]) and performance (sprinting speed [vsprint] and lactate thresholds [LT1 and 2]) factors were determined using a 500-m submaximal, 200-m all-out, 20-second sprint, and incremental test (+0.03 m·s-1, 3 min), respectively, in front-crawl swimming.RESULTS:vsprint (+0.6%) and LT1 and 2 (+1.9-2.4%) increased trivially and slightly, respectively, from T0 to T2 following small to moderate strength increases (≥+10.2%) from T0 to T1 and V˙O2peak (+6.0%) from T1 to T2. Bench-press maximal strength and peak power correlated with vsprint from T0 to T2 (r ≥ .54, P < .05) and LT2 at T1 (r ≥ .47, P < .05). Changes in fat percentage and V˙O2peak (T2-T1 and T3-T2, r ≤ -.67, P < .01) and C and LT2 (T2-T0, r = -.52, P = .047) were also correlated.CONCLUSIONS:Increases in strength and V˙O2peak from preparation to the competition period resulted in improved sprint and endurance performance. Across the season, upper-body strength was associated with vsprint and LT2, although their changes were unrelated.