Published papers

Purpose: This study aimed to examine the effects of a 12‑week hamstrings dynamic stretching (DS) program on joint flexibility, muscle strength, and musculoskeletal properties in the stretched limb, with the non‑stretched limb assessed for comparison. Methods: The study comprised 18 healthy young adults (12 males, 6 females) who performed hamstrings DS on one leg three times per week for 12 weeks, with the contralateral leg serving as the control. Pre- and post-intervention assessments included knee extension range of motion (KEROM), peak passive torque during KEROM (stretch tolerance), muscle stiffness, and knee flexor strength. Muscle stiffness was evaluated using shear-wave elastography targeting the biceps femoris (BF). Knee flexor strength was assessed using the rate of torque development (RTD) and isokinetic knee flexion torque. Results: KEROM significantly increased in the DS condition (p = 0.025; d = 0.61), with no significant change in the control condition (p = 0.55; d = 0.15). Peak passive torque significantly increased following DS (p = 0.041; d = 0.68), with no change in the contralateral limb (p = 0.21; d = 0.21). BF stiffness significantly decreased in the DS condition and remained unchanged in the contralateral limb (70° knee flexion: DS, p < 0.01, d = 0.79; control, p = 0.30, d = 0.30; 50° knee flexion: DS, p = 0.044, d = 0.55; control, p = 0.18, d = 0.34. RTD and isokinetic knee flexion strength did not change significantly in either condition. Conclusion: Twelve weeks of hamstrings DS enhanced stretch tolerance, reduced muscle stiffness, and improved joint flexibility in the stretched limb, with no notable changes observed in the contralateral limb. Trial Registration: Name of trial registry Effects of training and conditioning methods on mechanical properties of skeletal muscle Identifying number (URL) UMIN000051819 (https://center6.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000058080) Date of registration 5th Aug 2023.

Purpose – This study aimed to determine whether runners with mid-portion Achilles tendinopathy (Achilles tendinopathy runners [ATR]) show altered ankle-angle-dependent mechanical behavior of the Achilles tendon and triceps surae muscle–tendon unit during passive dorsiflexion. Methods – Twelve ATR and 11 control runners (CON) participated in this study (ATR: age 43.9 ± 12.0 years, running distance 38.3 ± 22.3 km/week; CON: age 41.2 ± 13.7 years, running distance 48.2 ± 29.7 km/week). The participants underwent device-controlled passive ankle dorsiflexion (DF) from 30° of plantar flexion (PF) to 80% of maximal DF at 1°/s in the prone position with the knee extended. Shear wave velocity (SWV) (m/s) was measured in the medial gastrocnemius (MG), lateral gastrocnemius (LG), soleus (SOL), and Achilles tendon (AT). The primary analysis used repeated-measures analysis of variance with angle (30/25/20/15/10/5/0° PF) and region (MG/LG/SOL/AT) as within-subject factors and group as the between-subject factor. A secondary triceps surae-only model (MG/LG/SOL) included 5/10/15° DF because the AT could not be measured beyond neutral. Results – In the primary model, the region × angle × group interaction was significant, and AT SWV was lower in ATR than in CON at 10° PF (ATR: 6.97 ± 0.49 vs. CON: 8.70 ± 0.51 m/s), 5° PF (ATR: 7.97 ± 0.43 vs. CON: 9.31 ± 0.45 m/s), and 0° PF (ATR: 9.15 ± 0.57 vs. CON: 11.30 ± 0.60 m/s) (all p < 0.05). The MG and SOL SWV were lower in ATR at all PF angles, whereas the LG showed no differences. In the secondary model, the MG and SOL remained lower in ATR across 5–15° DF. Conclusion – The ATR group showed lower Achilles tendon SWV near neutral and consistently lower MG and SOL SWV across ankle angles. These findings suggest altered ankle-angle-dependent mechanical behavior of the Achilles tendon and MG–SOL components of the muscle–tendon unit in runners with Achilles tendinopathy.

Abstract – Nishioka, T, Yamaguchi, S, Yoshikawa, A, Hajima, D, Yabuno, N, Aoki, A, Kunita, Y, Hashimoto, Y, and Inami, T. Integrating strength and technique: Field-based predictors of sprint running performance. J Strength Cond Res XX(X): 000–000, 2026—This cross-sectional study aimed to (a) examine the interrelationships among field-based indicators of strength qualities, sprinting technique, and sprint running performance; (b) identify the combination that best predicts sprint performance; and (c) determine whether sprinting technique explains additional variance beyond strength qualities. Thirty young, resistance-trained subjects performed 30-m sprint runs. Sprinting technique was assessed using the sprint mechanics assessment score (S-MAS) with a smartphone slow-motion 240-fps video. Strength qualities were assessed using the squat jump (SJ), countermovement jump (CMJ), bounce drop jump (BDJ), foot-ankle rebound jump (FARJ), and back squat (BSQ) 1 repetition maximum (1RM) tests. The S-MAS, SJ height, CMJ height, and FARJ reactive strength index (RSI) had significant and strong correlations with 30-m sprint time (ρ = 0.629, −0.629, −0.592, and −0.645, respectively; p < 0.001). The BDJ RSI and BSQ 1RM relative to body mass showed significant and moderate correlations with certain sprint times. Stepwise multiple linear regression analysis yielded a prediction equation (adjusted R2 = 0.561, p < 0.001) for 30-m sprint time, with FARJ RSI, SJ height, and S-MAS as significant independent variables (p < 0.05). The FARJ RSI and SJ height had negative partial regression coefficients (β = −0.324 and −0.355, respectively), and the S-MAS had a positive partial regression coefficient (β = 0.318). In conclusion, greater speed strength, foot-ankle reactive strength, and sprinting technique were strongly and independently associated with superior sprint running performance. Therefore, practitioners may benefit from targeting these strength and technical qualities, which can be regularly monitored using field-based assessments.

Accurate assessment of an individual force–velocity (F–V) profile is essential for prescribing targeted resistance training; however, F–V outcomes depend strongly on the testing method used. This study examined the concurrent validity of the F–V relationship in a horizontal leg press exercise by comparing two-point methods, which use pairs of different loads relative to body weight, with a multiple-point method using a wider range of loads. Sixteen men (mean ± SD, age: 20.0 ± 1.4 years, height: 172.4 ± 6.3 cm, body mass: 69.2 ± 7.6 kg) performed maximal-effort horizontal dynamic leg press actions on a device equipped with pneumatic artificial muscles (ddrobotec®, Switzerland) against eleven external loads (100%–300% of body weight [BW] in 20% increments). The F–V relationship was obtained using 10 two-point methods that paired a 100% BW load with each of the additional loads (120%–300% BW) and also from all points. The F–V relationship parameters were compared between the two-point methods and the multiple-point method, and their correlations were analyzed. The results showed that the F–V relationship obtained from the four two-point methods with wider load differences (100% and 240%, 100% and 260%, 100% and 280%, and 100% and 300% BW) was nearly perfectly correlated with that by the multiple-point method (r = 0.906 to 0.993). The concurrent validity of the F–V relationship parameters obtained from the two-point methods tended to decrease when using loads that were closer together (e.g., 100% and 120% BW) than loads with a larger difference (e.g., 100% and 240% BW). These findings indicate that, on a horizontal leg press with pneumatic artificial muscles, a two-point method based on sufficiently distinct loads can provide an accurate estimate of the F–V relationship and may be a practical alternative to comprehensive multi-load testing.

In aesthetic sports, performance is closely linked to body composition; however, quantitative indicators for monitoring athlete conditions remain limited. Bioelectrical impedance analysis-derived phase angle (PhA) reflects cellular health; however, its relationship with performance-related variables in rhythmic gymnasts remains unclear. This study explored the relationships among PhA, body composition, bone density, training time, and jump performance in senior rhythmic gymnasts across competitive levels. Twenty-three female gymnasts (aged 15–22 years) were classified into a top group consisting of athletes who had won major domestic competitions in Japan (n = 5) and a general group (n = 18). Body composition and PhA were assessed using bioelectrical impedance analysis, jump performance using the countermovement jump and reactive strength index, and bone density using the calcaneal ultrasound method. Although between-group differences were limited, distinct associations between PhA and performance-related variables were observed only in the top group. PhA was positively associated with skeletal muscle mass. In addition, a moderate, non-significant negative association between PhA and countermovement jump performance was observed in the top group. No clear relationships between PhA and body composition or jump performance were observed in the general group. Although these findings should be interpreted cautiously because of the small sample size and exploratory nature of the study, they suggest that the associations between PhA and performance-related variables may differ according to competitive level. Further studies with larger sample sizes and longitudinal designs are needed to clarify the relationships between PhA, performance-related variables, and physiological condition in rhythmic gymnasts.

Purpose: To investigate the acute effects of passive movement on rectus femoris (RF) stiffness, flexibility, and subjective knee joint pain in patients with Osgood-Schlatter disease (OSD). Methods: Patients with bilateral OSD at the orthopedic clinic between July 2023 and June 2025 were prospectively enrolled. One foot was randomly assigned to the intervention group (10 minutes of passive hip and knee joint movement), and the other was assigned to the control group (10 minutes of rest). The acute effects before and after the intervention (PRE and POST, respectively) were compared. RF stiffness was assessed PRE and POST using shear modulus values, heel-buttock distance, and subjective pain. A stratified cluster analysis of the treatment effect was performed based on the PRE shear modulus values in the intervention group (high-value and low-value groups). Results: Fifty-three participants diagnosed with bilateral OSD participated in the study. The RF shear modulus significantly decreased following the intervention (21.0 ± 4.4-17.5 ± 3.2 kPa) (P <.001), with the high-value group (–20.1 ± 9.6%) showing a significantly greater effect than the low-value group (–13.8 ± 8.6%) (P =.022). Depending on the threshold, 83.0% exceeded the minimal detectable change at the 95% confidence level, and 86.8% exceeded the smallest worthwhile change (0.2 standard deviation), while 66.0% exceeded the more conservative smallest worthwhile change (0.5 standard deviation). Heel-buttock distance and subjective pain significantly improved after passive movement (heel-buttock distance: 12.5 ± 4.7 to 9.3 ± 3.4 cm; subjective pain: 4.2 ± 2.4 to 2.6 ± 2.0 cm) (both P <.001). None of the parameters changed significantly in the control group. Conclusions: Ten minutes of passive hip and knee joint movement reduced RF stiffness in patients with OSD and improved knee joint flexibility and subjective pain. Furthermore, passive movement showed the greatest effect in the high-value shear modulus group. Level of Evidence: Level II, prospective comparative study.

Abstract – Nishioka, T, Yamaguchi, S, Hajima, D, Yabuno, N, Aoki, A, Kunita, Y, Hashimoto, Y, and Inami, T. Validity and reliability of a novel timing gate system for real-time measurement of sprint force-velocity profile. J Strength Cond Res XX(X): 000–000, 2026—The purpose of this study was to investigate the concurrent validity and intertrial reliability of a newly developed timing gate system, VoltOnoSprint (VOS), with a mat switch and smartphone app for real-time measurement of the sprint force-velocity (F-V) profile. Twenty-four men (age: 21.1 ± 2.1 years) performed two 30-m sprints. Subjects' body center of mass velocity and position-time data were measured simultaneously by radar and VOS, respectively, and were used to calculate the sprint F-V profile variables. All sprint F-V profile variables derived from VOS had significant, positive, and nearly perfect correlations (r = 0.905 to 0.964) with radar measurements and did not differ significantly (d = (Formula presented)0.073 to 0.110) from those derived from radar. The sprint F-V profile variables calculated using both systems exhibited acceptable intertrial reliability (intraclass correlation coefficient = 0.767 to 0.985, coefficient of variation = 0.88–4.81%), except for the relative reliability of one F-V profile variable (the slope of the F-V relationship) derived from radar. Furthermore, all sprint F-V profile variables derived from VOS had higher absolute variability than those derived from radar. These results suggest that VOS is a valid and reliable method for sprint F-V profiling, and the reliability of the sprint F-V profile variables measured by VOS was superior to that measured by radar, a criterion method. Therefore, VOS can be a valuable system for practitioners seeking real-time and accurate measurement of the sprint F-V profile.

Background/Objectives: Osgood–Schlatter disease (OSD) is a common overuse condition in adolescents characterized by increased stiffness of the rectus femoris muscle, which contributes to pain and functional limitations around the knee. We investigated whether repeating 10 min passive joint movements of the hip and knee produces additional immediate reductions in elevated rectus femoris (RF) stiffness in adolescents with OSD. Methods: Fifteen patients (10–14 years of age) diagnosed with bilateral OSD were included. The legs of the participants were randomly assigned to either the intervention or the non-intervention side (control). The intervention side received two sets of 10 min of passive joint movement to the hip and knee, while the control side rested. RF stiffness was measured before the intervention and immediately after one and two sets of passive joint movements. Results: On the intervention side, RF stiffness decreased significantly from pre to post-1 and from pre to post-2; however, RF stiffness did not differ significantly between post-1 and post-2. None of the parameters changed significantly on the control side (rest condition). Conclusions: Passive joint exercise beyond one repetition (one set for 10 min) did not result in a further decrease in RF stiffness and is likely unnecessary for RF muscle stiffness due to OSD.

Introduction – Since the distance between opponents constantly changes during fencing bouts, clarifying the relationship between movement type and target distance is important for understanding tactical movement selection. Methods – Twelve skilled male foil fencers performed lunges under six conditions combining three target distances (Short, Normal, Long) and two movement types (lunge without advance: LWOA; lunge with advance: LWA). Three-dimensional motion capture (500 Hz) was used to measure hip, knee, and ankle joint angles of the front and rear legs and center of mass (CoM) velocity. For each condition, the trial with the maximum horizontal peak CoM velocity was selected for analysis using a two-factor repeated-measures ANOVA. Results – Peak CoM velocity increased linearly with target distance and was consistently higher in LWA than in LWOA. The velocity difference between movement types was greatest at the Short distance and decreased at the Long distance. Correspondingly, rear-leg joint kinematics increased with target distance and were consistently larger in LWA than in LWOA, with significant interaction effects. Discussion – These findings suggest that the effectiveness of attack movements in fencing depends on the interaction between target distance and movement type. Fencers should select LWOA or LWA according to tactical distance while emphasizing rear-leg flexion and extension movements during training.

This study aimed to investigate the relationship between the break-point angle (BPA) measured with the Nordic Angle app and absolute and relative eccentric knee flexion peak torques. Twenty-one male participants performed Nordic hamstring exercise (NHE) trials to determine their BPA, followed by absolute eccentric knee flexion strength testing. Absolute eccentric knee flexion peak torque was divided by body weight to calculate relative eccentric knee flexion peak torque. No Pearson correlation was observed between BPA and absolute eccentric knee flexion peak torque (rp = −0.05, p = 0.85). Conversely, the Pearson correlation between BPA and relative eccentric knee flexion peak torque was significant (rp = −0.54, p < 0.05). BPA measured with the Nordic Angle application was associated with relative eccentric knee flexor peak torque. As this study did not include a clinical population nor investigate hamstring injury incidence, clinical implications should be interpreted cautiously, and future research is required to determine whether BPA can predict hamstring injury risk.

Purpose: Bodyweight eccentric exercise training (ET), in which eccentric contractions are prolonged while minimizing the effort for concentric contractions, is shown to improve the physical functions of older adults. No previous study has compared this with bodyweight resistance exercise training in which both concentric and eccentric contractions are performed slowly (CET). We hypothesized that CET would produce better health and fitness outcomes than ET. Methods: Healthy older adults (65–89 years) were placed into the ET (n = 21) or CET group (n = 19). Both groups performed several bodyweight resistance exercises at a community center once and at home more than twice a week for 10 weeks. In the exercises, each eccentric contraction was 3 s for both groups, but each concentric contraction was performed with as little effort as possible for ET, but 3 s for CET. Resting heart rate, blood pressure, knee extensor muscle thickness (MT), maximal voluntary contraction strength (MVC), physical function tests (30-s chair stand: CS, 3-m timed up and go: TUG, sit and reach, 6-m walking time: 6WT and static balance) were assessed before and after the 10-week training, and their changes were compared between groups. Results: The subjective exercise intensity was lower (P < 0.01) for ET (2.2 ± 1.8/10) than CET (3.2 ± 1.7). Greater improvements in resting heart rate, blood pressure, CS, TUG, and 6WT were found for ET than CET, but MT and MVC increased similarly for both groups (P < 0.05). Conclusion: These results did not support the hypothesis in the present study design and showed that eccentric-focused training yielded greater benefits than slow concentric–eccentric training.

The stiffness of the triceps surae (TS) muscles during passive stretch has been increasingly studied using shear wave elastography (SWE). However, the continuous behavior of the Achilles tendon (AT) and its interaction with the TS muscles remain poorly understood, limiting understanding of tissue mechanics. This study aimed to characterize the angle-specific stiffness profiles of the individual TS muscles—the medial gastrocnemius (MG), lateral gastrocnemius (LG), and soleus (SOL)—and the AT during passive ankle dorsiflexion under identical experimental conditions. In this cross-sectional study, the ankles of 24 healthy university track and field athletes (age, 20.2 ± 1.3 years) were passively moved by a dynamometer from 30° of plantar flexion (PF) to 80% of maximum dorsiflexion (DF) at 1°/s (up to 25° DF). Shear wave velocity (SWV), an index of tissue stiffness, was measured at four sites (MG, LG, SOL, and AT). The percentage change in SWV from the −30° baseline was analyzed at 5° increments up to the neutral (0°) position using two-way analysis of variance. Significant SWV increases from baseline were observed at 10° PF for the MG, 5° PF for the LG, and 25° PF for the SOL. In contrast, the AT showed significant increases from 25° PF onward, with a rate of change consistently greater than that of all TS muscles across all measured angles. These findings indicate that the AT and TS exhibit asynchronous stiffening patterns: the tendon provides immediate resistance from the earliest range of motion, while the muscles remain compliant until further stretched. Thus, the tendon, rather than the muscle, primarily governs the initial resistive behavior of the muscle–tendon unit during passive stretch. Understanding this angle-specific behavior is essential for optimizing load management in rehabilitation and injury prevention.

We aimed to compare the concurrent validity of force–velocity (F–V) profiling using two low-cost and accessible jump height (JH) calculation methods: flight time method (FT) and modified FT (FTM). Forty-two male athletes performed unloaded, moderate-, and high-loaded squat jumps and countermovement jumps on force plates while recorded with a high-speed smartphone camera. JH was calculated using the impulse-momentum method (IM), FT, and FTM, and values were subsequently used to derive F–V profile variables. The FT significantly overestimated some F–V profile variables of the countermovement jump. Conversely, all F–V profile variables calculated using the FTM did not differ significantly from those derived using the IM. Moreover, F–V profile variables derived using the IM were more strongly correlated with those calculated using the FTM than those calculated using the FT. In conclusion, the FTM demonstrates higher concurrent validity for assessing F–V profiles than the FT.

The study aimed to investigate the relationships between the shear modulus of the biceps brachii (BB) and brachialis muscle (BA) and the total of the two (BB+BA), and urinary titin N-terminal fragment (UTF), maximum voluntary isometric contraction (MVC), and other indirect markers. Fifteen healthy men performed five sets of 10 eccentric contractions using a dumbbell corresponding to 50% of MVC at 90° measured at baseline. The elbow joint of the left arm was extended from 90° to 180° (180° = full extension) in 5 s in the exercise, and was returned with support from the examiner to prevent concentric contraction. Shear modulus of BB and BA were measured by ultrasound shear wave elastography, and UTF, MVC, and range of motion of the elbow joint (ROM) were recorded before; immediately after; and 1, 24, 48, 72, 96, and 168 h after the exercise. After calculating the shear modulus of BB and BA, two values were added (BB+BA). The shear modulus peaked at 48 h, UTF peaked at 96 h, MVC and ROM changed largest at immediately, and muscle soreness peaked at 48 h post-exercise. Significant (p < 0.05) relationships were found between changes in BB shear modulus and BA shear modulus (r = 0.874), BB+BA shear modulus (r = 0.977), UTF (r = 0.681), and MVC (r = -0.538). Significant (p < 0.05) relationships were also observed between changes in BA shear modulus and BB+BA shear modulus (r = 0.957), UTF (r = 0.682), MVC (r = -0.522), and ROM (r = -0.600). Moreover, significant (p < 0.05) relationships were observed between changes in BB+BA shear modulus and UTF (r = 0.703), MVC (r = -0.549), and ROM (r = -0.547). These results indicate that shear modulus of each muscle (i.e., BB and BA) provide more precise information about muscle damage than UTF, MVC and ROM.

Background/Objectives: In this study, we aimed to examine the effect of creatine monohydrate (CrM) supplementation on recovery from eccentric exercise-induced muscle damage (EIMD) in diverse populations, including different sexes and age groups. EIMD decreases maximal voluntary contraction (MVC), restricts the range of motion (ROM), and increases muscle stiffness and delayed-onset muscle soreness, all of which negatively impact athletic performance. Therefore, developing effective recovery strategies is essential. Methods: A double-blind, randomized, placebo-controlled trial was conducted with 40 healthy male and female participants. After 33 days of supplementation with either CrM or placebo (crystalline cellulose), the participants performed eccentric exercises. Recovery indices, including MVC, muscle stiffness, subjective muscle extensive soreness, fatigue, and upper arm circumference, were measured at baseline, immediately after exercise, 48 h post-exercise, and 96 h post-exercise. Results: The creatine supplementation group (CRE) demonstrated a significantly quicker recovery of MVC than the placebo group (PLA). Furthermore, reductions in shear modulus and muscle fatigue were observed in the CRE group. Notably, females in the CRE group exhibited a significant suppression of post-exercise edema, suggesting a sex-specific response. Conclusions: These findings indicate that CrM supplementation may enhance recovery from EIMD, contributing to the maintenance of muscle function and the reduction of discomfort after exercise. CrM has the potential to serve as a practical nutritional strategy to promote recovery, not only for athletes, but also for a broader population.

Purpose: To investigate the effects of full marathon running on intrinsic and extrinsic foot muscle damage and to determine the relationship with the height change of the longitudinal foot arch following full marathon completion. Methods: Magnetic resonance imaging-measured transverse relaxation time (T2) of the abductor hallucis (ABH), flexor digitorum brevis (FDB) and quadratus plantae (QP), flexor digitorum longus (FDL), tibialis posterior (TP), and flexor hallucis longus (FHL) from 22 collegiate runners were assessed before and 1, 3, and 8 days after full marathon running. The three-dimensional foot posture of 10 of the 22 runners was further obtained using a foot scanner system before and 1, 3, and 8 days after the marathon. Results: Marathon-induced increases in T2 were observed in the QP, FDL, TP, and FHL 1 day after the marathon (+7.5%, +4.7%, +6.7%, and +5.9%, respectively), with the increased T2 of TP persisting until 3 days after the marathon (+4.6%). T2 changes of FDL and FHL from pre-marathon to DAY 1 showed direct correlations with the corresponding change in the arch height ratio (r = 0.823, p = 0.003, and r = 0.658, p = 0.038). Conclusion: The damage and recovery response from a full marathon differed among muscles; QP, FDL, TP, and FHL increased T2 after the marathon, whereas ABH and FDB did not. In addition, T2 changes in FDL and FHL and the arch height ratio change were correlated. Our results suggest that the extrinsic foot muscles could be more susceptible to damage than the intrinsic during marathon running.

Ice slurry ingestion enhances exercise performance by lowering the core body temperature. However, an operational issue related to this ingestion is the requirement for a high intake of 7.5 gkg-1 to produce the desired effects. We investigated the effects of the intake of low amounts of ice slurry at ?2?C on the tympanic temperature and exercise performance during repeated high-intensity intermittent exercises in a hot environment. This study was a randomized, crossover study, with a 6-day washout period. Twelve university rugby union players performed two 30-min sessions of high-intensity intermittent exercises separated by a 15-min half-Time break on a cycle ergometer in a hot environment (28.8?C 0.1?C, 49.5% 0.6% relative humidity). The participants ingested 450 g of ?2?C-ice slurry (ICE), or a 30?Cbeverage (CON) having the same composition as ICE, or 30?C-water (WAT) during the halftime break. The tympanic temperature and skin temperature were measured as the physiological data, and the peak power and mean power as the exercise performance data. The tympanic temperature at the half-Time break and beginning of the 2nd session was significantly lower in the ICE group as compared with the CON and WAT groups. The skin temperature at the half-Time break was significantly lower in the ICE group as compared with the WAT group. While the peak power and mean power during the 2nd session were significantly greater in the ICE group as compared with the CON and WAT groups. Our findings suggest that even the intake of lower amounts, as compared with those used in previous studies, of low-Temperature ice slurry can reduce the body temperature and improve the peak power. These results suggest that intake of low-Temperature ice slurry as a strategy for internal body cooling is useful for improving endurance exercise performance in hot environments.

Background: Glucose and lipid tolerance reportedly exhibit diurnal variations, being lower in the evening than in the morning. Therefore, the effects of exercise on glucose and blood lipid levels at different times of the day may differ. This study aimed to investigate the effects of short-term endurance exercise intervention in the morning versus late afternoon on 24-h blood glucose variability and blood lipid levels. Methods: Twelve healthy young men participated in a randomized crossover trial. The participants were assigned to morning (09:00–11:00) or late afternoon (16:00–18:00) endurance exercise for a week, consisting of supervised exercise sessions on Mondays, Wednesdays, and Fridays. In the morning and evening trials, the participants walked for 60 min on a treadmill at approximately 60% of maximal oxygen uptake (VO2max). Following a 2-week wash-out period, the participants performed the exercise training regimen at another time point. Continuous glucose monitoring was used to evaluate blood glucose fluctuations during each 24-h trial period. Blood samples were collected before and after each intervention to examine blood lipid and hormonal responses. Results: Examination of the area under the curve (AUC) of the glucose level changes for 24 h after the late afternoon versus morning exercise intervention revealed significantly lower values for the former versus the latter (P < 0.01). The AUC of glucose level changes after each meal was also lower after the late afternoon versus morning intervention, and significantly lower values were observed in the late afternoon versus morning trial for breakfast and dinner (P < 0.05, P < 0.01). In addition, a significant decrease in triglycerides (TG) and TG/high-density lipoprotein cholesterol (HDL-C) was noted after versus before the late afternoon intervention (P < 0.05). Conclusions: These results suggest that late afternoon endurance exercise is more effective than morning endurance exercise at improving 24-h glucose and triglyceride levels.

We investigated the influence of advance lunging in fencing from the perspective of velocity and lower limb joint angles to identify how the joint angles contribute to the peak velocity in a lunge with advance (LWA). Fourteen skilled athletes (age: 19.6 ± 0.9 years, height: 171.2 cm ± 5.2 cm, weight: 63.7 kg ± 5.3 kg, and fencing experience: 9.7 ± 3.1 years) participated by performing two types of attacking movements, and data were collected with a 3D movement analysis system. A correlation between the peak velocity of the body center of mass (CoM) in an advance lunge and several joint angle variables (rear hip peak flexion angle (r = 0.63), rear ankle peak dorsiflexion angle (r = −0.66), rear ankle range of motion (r = −0.59), and front hip peak extension angle (r = 0.54)) was revealed. In addition, the joint angle variables that significantly predicted peak CoM velocity during an LWA were the rear knee peak flexion angle (β = 0.542), rear knee peak extension angle (β = −0.537), and front knee peak extension angle (β = −0.460). Our findings suggest that the rear leg hip joint, rear leg ankle joint, and front leg hip joint may control the acceleration generated by an LWA. Furthermore, more flexion of the rear leg knee joint in the early phase of the lunge and greater extension of the rear and front leg knee joints at the end of the lunge phase may help increase peak velocity.

This study aimed to evaluate the effects of different target distances on various leg joints in the fencing lunge (lunge). Fifteen fencers performed the lunges from three different target distances (normal, short, and long). Joint angle data in the sagittal plane of the hip, knee, and ankle of the front and rear legs were measured using a 3D motion analysis system (Miqus M3). Joint angle variables were compared between each distance using a one-way repeated-measures analysis of variance and Friedman tests (p < 0.05). The results showed significant differences in various extensions, ranges of motion, and flexion angles in the measured joints for all distances. As the distances increased, there was greater flexion of the rear knee joint early during the lunge, followed by greater extension of the rear hip and knee joints, greater plantar flexion of the rear ankle joint, and higher peak velocity of the body center of mass. Furthermore, target distance extension was suggested to significantly affect front hip and knee joint flexion during the braking phase of the lunge. This study provides insight and information valuable to coaches and fencers operating in actual competition settings.