Acute Effects of a Hop-Stabilization Warm-Up Program on Dynamic Balance, Ground Reaction Force, and Muscle Activity During Cutting Movements in Collegiate Athletes with Chronic Ankle Instability.

First-time lateral ankle sprains often lead to chronic ankle instability (CAI), with 47% facing recurrent injuries, emphasizing the need for preventive measures. Side-cutting movements in sports pose a risk for CAI individuals due to potential biomechanical control alterations. While the hop-stabilization warm-up program has proven effective in preventing ankle sprains, its specific acute impact on CAI individuals lacks substantial evidence. This study employed a crossover design with eight CAI participants (23 ± 3.4 years, BMI 23 ± 1.5 kg/m2) and eight healthy participants (25 ± 3.6 years, BMI 23 ± 1.7 kg/m2) to investigate the acute effects of the hop-stabilization warm-up program on dynamic balance, ground reaction force (GRF), and muscle activity during 45- and 90-degree side-cutting movements. Each participant underwent hop-stabilization and control warm-up programs on two experimental days. Assessments, including the Y-balance test, GRF, and muscle activity pre- and post-warm-up, revealed significant improvements in dynamic balance, GRF, and muscle activity during 45-degree side-cutting movements in CAI participants. These findings suggest the potential benefits of incorporating the hop-stabilization warm-up program into the warm-up protocol for individuals with CAI.

Effects of an integrative warm-up method on the range of motion, core stability, and quality of squat performance of young adults.

Introduction: This research aims to determine the effects of an integrative warm-up method on the range of motion in joints of the lower extremities, the strength of the stabilizer trunk muscles, and the quality of the basic movement patterns in older adolescents. Methods: The study sample consisted of 88 male students (age 20.1 ± 0.5). They were randomly divided into four groups: one control group (CG) (n = 17; 180.8 ± 7.9 cm; 82.3 ± 8.3 kg) and three experimental groups (EG): EG1 (n = 23; 180.9 ± 7.0 cm; 78.5 ± 9.5 kg), EG2 (n = 31; 182.2 cm ± 7.3 cm; 79.5 ± 11.5 kg), and EG3 (n = 17; 183.3 ± 4.9 cm; 77.5 ± 11.8 kg). The participants were subjected to a 6-week experimental treatment: EG1 once, EG2 twice, and EG3 three times a week. The experimental treatment consisted of four sub-phases representing the integrative warm-up Method: 1) Inhibition (self-myofascial release using a foam roller); 2) Lengthening (Static stretching in a maximum range of motion position); 3) Activation (Positional isometrics muscle activation of the trunk and gluteus); 4) Integration (Integrated all the previous phases into one complex movement pattern). Based on the covariance analysis (ANCOVA), statistically significant treatment effects were observed and positive changes were determined in all experimental groups. Results: The differences between groups were observed in the following variables: Overhead Squat Assessment (p = 0.000; ηp2=0.318), range of motion of left hip flexion (p = 0.000; ηp2=0.371), range of motion of right hip flexion (p = 0.000; ηp2=0.051) and range of motion of right hip extension (p = 0.051; ηp2=0.088), Double Leg Lowering Test (F = 2.411; p = 0.014; ηp2=0.014) and range of combined motion (plantar and dorsiflexion) of left ankle joint (p = 0.000; ηp2=0.299). There was no significant difference in the Plank Test (F = 1.007; p = 1.007; ηp2=0.035), range of combined motion (plantar and dorsiflexion) of right ankle joint (p = 0.088; ηp2=0.170) and range of motion of left hip extension (p = 0.158; ηp2=0.060). The participants of CG statistically significantly differed from EG1, EG2, and EG3 in the squat performance after the applied treatment. Discussion: The effect of the treatment was the occurrence of a transformational processes in almost all measured variables. It can be concluded that the integrative method is effective and applicable in practice for both young adults and recreational athletes.

Examining the Influence of Warm-Up Static and Dynamic Stretching, as well as Post-Activation Potentiation Effects, on the Acute Enhancement of Gymnastic Performance: A Systematic Review with Meta-Analysis.

The primary objective of this systematic review with meta-analysis is to methodically discern and compare the impact of diverse warm-up strategies, including both static and dynamic stretching, as well as post-activation potentiation techniques, on the immediate performance of gymnasts. Adhering to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, this paper evaluated studies that examined the gymnasts' performance after different warm-up strategies namely stretching (static [SS] or dynamic), vibration platforms (VP) or post-activation, in comparison to control conditions (e.g., mixed warm-up routines; no warm-up). The principal outcomes were centered on technical performance metrics (e.g., split, gymnastic jumps) and physical performance metrics (e.g., squat jump, countermovement jump, drop jump, balance, range of motion). Methodological assessments of the included studies were conducted using the Downs and Black Checklist. From the initial search across PubMed, Scopus, and the Web of Science databases, a total of 591 titles were retrieved, and 19 articles were ultimately incorporated in the analysis. The results revealed a non-significant differences (p > 0.05) between the SS condition and control conditions in squat jump performance, countermovement jump and gymnastic technical performance (e.g., split; split jump). Despite the difference in warm-up strategies and outcomes analyzed, the results suggest that there is no significant impairment of lower-limb power after SS. Additionally, technical elements dependent on flexibility appear to be enhanced by SS. Conversely, dynamic stretching and VP seem to be more effective for augmenting power-related and dynamic performance in gymnasts.

Impact of warm-up methods on strength-speed for sprinters in athletics: a mini review.

In athletics, achieving peak performance during competitions is crucial. Warm-up strategies play a crucial role in optimizing the strength-speed performance of sprinters in athletics, especially tailored to the physiological demands of speed events. The need to balance flexibility, prevent injuries, and enhance power output makes the selection of an effective warm-up protocol essential. This narrative review examines different warm-up methods used by athletes and their effects on strength-speed in sprinters in athletics. The main findings indicate that Foam Rolling (FR), Isometric Exercises and Pre-Competitive Massages have no significant effects on sprint performance. Static stretching and prolonged Pre-Competitive Massages have negative impacts on strength and power. The Vibration Platform enhances step length, step rate and running velocity, jump height and total number of jumps performed in a 30-s period in non-experienced sprinters. Eccentric Exercise increases vertical force, Post-Activation Potentiation (PAP) demonstrates a reduction in 100-meter time and short-term improvement in vertical and horizontal jumps. Blood Flow Restriction (BFR) significantly improving jump height and flight time. Various warm-up methods have been identified, some focusing on flexibility, others potentially detrimental, and some enhancing strength and power. Implementing effective warm-ups, particularly those promoting strength and power, poses a challenge for coaches seeking reliable alternatives to boost performance.

Warm-Up Strategies and Effects on Performance in Racing Horses and Sport Horses Competing in Olympic Disciplines.

Warm-up is a standard component of exercise preparation, intended to lower the risk of injury and improve performance. Comprehensive evidence-based guidelines per discipline are missing. This scoping review aimed to describe the physiological effects and strategies of active warm-up in horses according to different equestrian disciplines. The search strategies identified 479 papers for review. After application of selection criteria, 23 articles published from 1996 to January 2024 were included of which 12 discussed the effects of warm-up on physiological parameters and 11 discussed warm-up strategies in different disciplines. As shown in humans, warm-up enhanced aerobic capacity and increased blood and muscle temperatures, independently from its intensity. Riders emphasized the importance of warm-up to prepare horses for physical work and to increase their reactiveness to aids. A canter or trot was the preferred gait in elite or non-elite dressage horses, respectively, while the walk was in show jumping horses. Warm-up duration and intensity increased with increasing competitive level, but a longer and/or more intensive warm-up did not affect the final score. Dressage riders warmed up their horses for a longer time compared to show jumping riders. Future studies should objectively establish the most profitable warm-up strategies per equestrian discipline and level.

Does the sequence of plyometric and dynamic stretching exercises influence subsequent sprint performance? A randomized crossover intervention study.

The objectives of this study were to evaluate the acute effects of the sequence order of drop jumps (DJ) and dynamic stretching (DS) on sprinting performances in competitive athletes and to investigate the relationships between post-activation performance enhancement (PAPE) in sprint performance and lower limb power. Thirteen male jumpers and sprinters participated in this study (19 ± 2 years; 177 ± 7 cm; 71.7 ± 5.6 kg). Through a randomized crossover design, the athletes were exposed to three different conditions after a standardized warm-up: DS+DJ, DJ+DS, and control. Sprinting performance over 40 m was analysed with consideration of initial (0 to 20 m) and final acceleration (20 to 40 m) phases. The effect of intervention was examined by two-way repeated-measures of ANOVA. Pearson's correlation test was used to determine the association between PAPE during sprinting and jump performance. There was no effect of any factor on 40-m sprint performance. Meanwhile, the performance at 20-40 m was higher after the DS+DJ condition when compared to baseline (8.79 ± 0.43 vs. 8.91 ± 0.35 m/s; p = 0.015). However, the initial acceleration was worsened in the DJ+DS condition when compared to baseline (6.26 ± 0.25 vs. 6.22 ± 0.26 m/s; p = 0.002). There was a negative correlation between CMJ height and the improvement in final acceleration (r = -0.741; p = 0.004). The use of DS prior to DJ is an effective strategy to improve performance in the final acceleration phase (20-40 m). The athletes with lower levels of lower limb power benefited the most from this PAPE strategy.

Comparison of acute and prolonged effects of short-term foam rolling and vibration foam rolling on the properties of knee extensors.

Recently, Foam Rolling (FR) and Vibration Foam Rolling (VFR) have attracted attention in sports and rehabilitation fields. Previous studies have shown that FR and VFR acute interventions effectively increase the range of movement (ROM) and decrease tissue hardness. For application to sports and rehabilitation, it is necessary to compare the acute and prolonged effects of short duration FR and VFR. Therefore, this study aimed to compare and investigate the acute and prolonged (15 minutes) effects of short duration (30-s) FR and VFR interventions on knee extensors. The subjects were 14 male university students (22.4 ± 1.0 years old), in which the knee extensors of the dominant leg were tested. In a cross-over trial, 30-s of FR or VFR were performed with 2-s rolling of the anterior thigh (15 rolls). The frequency of VFR was 35 Hz. Measurements included knee flexion ROM, pain pressure threshold (PPT), tissue hardness, and countermovement jump height. The results of this study showed no interaction effects for all variables, but main time effects were observed for knee flexion ROM, PPT, and tissue hardness. Post-hoc tests showed that knee flexion ROM increased up to 10 minutes after the intervention. PPT significantly increased, and tissue hardness significantly decreased up to 15 minutes after intervention. This study showed that 30-s FR and VFR interventions effectively increased ROM, PPT, and decreased tissue hardness. The effects were prolonged up to 10-15 minutes after the intervention. The results of this study show no advantage of VFR over FR with acute short-term interventions.

The Acute Effect of Dynamic vs. Proprioceptive Neuromuscular Facilitation Stretching on Sprint and Jump Performance.

Participating in sports has been shown to promote overall wellness and, at the same time, reduce health risks. As more people are participating in sports, competitions have increased, and every aspect of the game has been focused by coaches and athletes in order to improve performance. One of these aspects is the warm-up session. The purpose of this study was to investigate the acute effect of a dynamic warm-up versus a proprioceptive neuromuscular facilitation (PNF) warm-up on the sprint and jump performance of recreationally active men. Thirty (n = 30) males were randomly assigned to undergo three sessions of different warm-up types, 72 h apart, involving either proprioceptive neuromuscular facilitation (PNF), dynamic stretching (DS), or no stretching session (control). The PNF and dynamic modes of stretching improved vertical jump performance, F (2.58) = 5.49, p = 0.046, to a certain extent (mean + 3.32% vs. control, p = 0.002 for dynamic and mean + 1.53% vs. control, p = 0.048 for PNF stretching). Dynamic stretching is best used to get a better vertical jump height. Sprint performance was also increased to a greater extent following the stretching session, F (2.58) = 5.60, p = 0.01. Sprint time was +1.05% faster vs. the control, with a value of p = 0.002 after dynamic stretching, while PNF stretching demonstrated a sprint time of +0.35% vs. the control, with a value of p = 0.049. Dynamic stretching showed a better sprint performance and also vertical jump height performance in this study. PNF and dynamic stretching prove to be equally efficacious in flexibility conditioning depending on the type of movement involved. This type of stretching should be utilized to help preserve or improve the performance output of physical activity, especially in sprinting and jumping events.

Suggestions and Considerations for Application of Movement Screens to Clinical Practice.

Pre-participation and return to activity functional assessments are commonly used in clinical practice to assess movement quality and identify athletes' limitations. While there are slight differences between each specific test battery, general guidelines suggest that the tests be completed without a warm-up. This has been suggested because dynamic stretching may improve range of motion and athletic performance. However, athletes typically warm up prior to participating in sport. Therefore, researchers should investigate the acute effects of dynamic stretching on functional tests and movement screens and evaluate other factors that may influence performance on these test batteries. Scientific evidence for standardized implementation of various movement screens is lacking, and future research should aim to identify gaps in the literature to allow clinicians to properly implement evidence-based practice functional assessments. The purpose of this commentary is to discuss various considerations for implementing movement screens and assessment tools into clinical practice. LEVEL OF EVIDENCE: 5.

Warm-up exercises reduce music conservatoire students' pain intensity when controlling for mood, sleep and physical activity: A pilot study.

Introduction: Playing-related musculoskeletal pain is highly prevalent among classical music students, affecting them physically and psychologically. Unlike athletes or dancers, musicians' pain often goes untreated due to stigma and lack of specialised healthcare. While warm-up exercises are common practice in sports and dance, there is a lack of empirical research regarding physical warm-ups for musicians' pain. This study aimed to investigate the effects of a 2-week daily warm-up exercise intervention on conservatoire students' pain intensity, interference and psychological distress, at day 0 and after 2 weeks. Methods: Two groups were considered: an exercise (n = 9) and a waitlist control (n = 7) group. Data were collected using online Qualtrics surveys at three different stages. Results: 2 × 2 mixed ANOVAs indicated no significant effects on any of the outcome variables. However, when controlling for sleep, anxiety, depression and physical activity, the analyses revealed a significantly greater decrease in pain intensity in the exercise group compared to the control. In addition, bivariate correlations indicated that pain interference, anxiety and depression delta scores were significantly correlated for the exercise but not the control group. Anxiety and pain intensity delta scores were significantly correlated in both groups. Conclusions: These findings suggest that daily warm-up exercises have the potential to reduce musicians' pain intensity but only if certain variables are factored in. This pilot study highlights the multifactorial nature of musicians' pain and unveils the role that mood, sleep and physical activity level may have when assessing the efficacy of interventions based on warm-up exercises.

Effects of Static Hamstring Stretching on Maximal Sprint Speed and Relationship With Nordic Hamstring Strength.

This study aimed to determine the acute effects of static stretching of the hamstrings on maximal sprint speed and its spatiotemporal variables and lower-limb kinematics during the late swing phase, as well as the relationship with Nordic hamstring strength. The study had a within-participant experimental design. Sixteen healthy male college sprinters were asked to sprint 80 m without static stretching and with static stretching of the hamstrings for 4 × 30 s per leg before the sprint; both conditions were counterbalanced. The knee flexion peak torque was measured using the Nordic hamstring. The differences between no static stretching and static stretching as well as their relationship with Nordic hamstring strength were investigated. The results showed that the touchdown distance (p = .036) significantly increased following static stretching. Although not significant, maximal sprint speed decreased (p = .086), and the theoretical hamstring length (difference between knee angle and hip angle) at ipsilateral touchdown was greater (p = .069) following static stretching. In addition, a lower peak torque of the Nordic hamstring resulted in a more significant decrease in maximal sprint speed following static stretching. Therefore, static stretching of the hamstring just before sprinting may increase the theoretical hamstring length during the late swing phase at maximal sprint speed and induce kinematics that increases the hamstring strain injury risk. Moreover, it is suggested that improving the Nordic hamstring strength may help minimize the negative effects of static stretching on the hamstrings.

Immediate effects of the semi-occluded bubble mask technique using VocalFeel® device as vocal warm-up in singers.

OBJECTIVE: The present study aims at investigating the immediate effects of the Semi-Occluded Bubble Mask Technique (SOBM) performed with the device VocalFeel® as a vocal warm-up in a group of professional singers. STUDY DESIGN: A randomized controlled study was carried out. METHODS: Forty-four vocally healthy professional singers were randomly divided into two groups on recruitment: an experimental group and a control group. The same vocal warm-up exercise was performed by the experimental group with the SOMB technique and by the control group without semi-occlusion. Self assessments, acoustic analysis and aerodynamic analysis of Peak Nasal Inspiratory Flows (PNIF) and Peak Oral Inspiratory Flows (POIF) were performed. RESULTS: Significant improvements after the SOBM technique were detected in the experimental group concerning some acoustic parameters (Jitt%; Shimm%) and aerodynamic measures (PNIF and POIF). No significant improvements after the warm-up exercise were observed in the control group. Significant differences between the experimental and the control group were found for ΔJitt%, ΔShimm%, ΔNHR, ΔPOIF and self assessments. CONCLUSIONS: The results of the present study support the efficacy of a vocal warm-up performed with the SOBM technique using VocalFeel® device in terms of acoustic quality, aerodynamic measures and perceived phonatory comfort in professional singers.

Effects of preoperative surgeon warm-up in video-assisted thoracoscopic surgery lobectomy.

BACKGROUND: In various surgical specialties, preoperative surgical warm-up has been demonstrated to affect a surgeon's performance and the perioperative outcomes for patients. However, the influence of warm-up activities on video-assisted thoracoscopic surgery lobectomy (VATSL) remains largely unexplored. This study aims to investigate the potential effects of preoperative surgical warm-up on VATSL. METHODS: A cohort of 364 patients diagnosed with lung cancer through pathology and undergoing VATSL at the Thoracic Surgery Department of Xuzhou Medical University from January 2018 to September 2022 were included. Patients were categorized into two groups: the warm-up group, comprising 172 patients undergoing their first VATSL of the day, and the warm-up effect group, consisting of 192 patients undergoing their second VATSL on the same day. Propensity score matching was employed to compare operation times and postoperative complications between the two groups, resulting in 159 matched cases in each group. RESULTS: There were no statistically significant differences in operation time (154.5 ± 54.9 vs. 147.2 ± 54.4 min, p = 0.239) and postoperative complications (including pulmonary infection, atelectasis, long-term pulmonary air leakage requiring incision suture in the operating room, and postoperative pleural effusion) (14:22 cases, p = 0.157) between the warm-up and warm-up effect groups. CONCLUSION: The findings suggest that preoperative surgical warm-up does not significantly affect the perioperative outcomes of VATSL.

Effects of stretching in a pilates program on musculoskeletal fitness: a randomized clinical trial.

BACKGROUND: The scientific literature questions the impact of stretching exercises performed immediately before muscle strengthening exercises on different components of musculoskeletal physical fitness. Pilates is a physical exercise modality that typically uses stretching exercises preceding muscle-strengthening exercises. However, no studies have investigated the effects of stretching in a Pilates program on components of musculoskeletal fitness. The aim of the present study was to verify the effects of stretching in a Pilates exercise program on flexibility, strength, vertical jump height and muscular endurance. METHODS: Thirty-two sedentary young women were randomized into two groups: traditional Pilates (TP), who performed flexibility and muscle strengthening exercises (n = 16), and nontraditional Pilates (NTP), who only performed muscle-strengthening exercises (n = 16). Sessions took place 3 times a week for 8 weeks. The following tests were performed pre- and postintervention: 10-RM knee extensors, vertical jump, handgrip, 1-min sit-ups, Sorensen and sit-and-reach. The occurrence of adverse events was recorded throughout the intervention and compared between groups using odds ratio (OR). To compare the results of motor tests between groups, ANCOVA or Mann‒Whitney U test was used for parametric and nonparametric data, respectively. The data were analyzed by intention-to-treat. RESULTS: After intervention, the TP was superior to NTP for the sit-and-reach test, with a large effect size (d = 0.87; p = 0.035), with no differences between groups for the other tests. Intragroup comparisons showed significant differences (p < 0.05) for TP and NTP for improvement in 10-RM knee extensors and vertical jump measurements, while only TP showed significant intragroup improvement (p < 0.05) for the sit-and-reach test. A greater chance of experiencing pain or other discomfort as a result of exercise was shown by NTP (OR = 4.20, CI95% 0.69 to 25.26). CONCLUSION: Our findings demonstrated that stretching exercises performed at the beginning of sessions in a Pilates program did not impair or enhance the development of strength, vertical jump height and muscular endurance in young women. However, only the Pilates program with stretching improved flexibility and reduced the chances of adverse events such as musculoskeletal pain and other discomfort resulting from the exercise protocol. CLINICALTRIALS: GOV: NCT05538520, prospectively registered on September 16, 2022.

Effects of percussion massage therapy, dynamic stretching, and static stretching on physical performance and balance.

BACKGROUND: Percussion massage therapy is a popular approach in sport medicine for physical therapists, but few researchers have investigated the comparison with other intervention methods. OBJECTIVE: This study aimed to examine the comparison of the effects of dynamic stretching, static stretching and percussive massage therapy on balance and physical performance in individuals. METHODS: The participants who were 18-25 years of age, able to perform performance tests, did not have any orthopedic surgery, did not have problems during running and sudden turning, and did not have a professional sports history were included in the study. Participants were assigned randomly to three groups as dynamic stretching (DS) (n= 16), static stretching (SS) (n= 16) and percussive massage therapy (PMT) (n= 16) groups. Horizontal jumping test, T drill test and balance measurements on a single leg with open and closed eyes of all participants were recorded before and after applications. RESULTS: When the values of the pre and post-treatment of all groups in the study were compared, significant improvements were observed in the t-test, horizontal jumping test and right/left foot balance with eyes open in DS group (p< 0.05). Significant improvements were observed in all values in the PMT group (p< 0.05). In the comparison of the differences between the groups, PMT group values were more significant than the SS group in all parameters. CONCLUSION: Percussive massage therapy would be an alternative that can be used to increase the performance and balance of individuals before exercise.

Acute effects of static and proprioceptive neuromuscular facilitation stretching on hamstrings muscle stiffness and range of motion: a randomized cross-over study.

This study aimed to compare the acute effects of static stretching (SS) and proprioceptive neuromuscular facilitation (PNF) stretching on hamstrings flexibility and shear modulus. Sixteen recreationally active young volunteers participated in a randomized cross-over study. Participants underwent an aerobic warm-up (WU), followed by either SS or PNF stretching. Range of motion (RoM) during passive straight leg raise and active knee extension, as well as shear modulus of the biceps femoris (BF) and semitendinosus (ST) muscles, were measured at baseline, post-WU, and post-stretching. Both stretching techniques significantly increased RoM, with no differences observed between SS and PNF (p < 0.001; η2 = 0.59-0.68). However, only PNF stretching resulted in a significant decrease in BF shear modulus (time×stretching type interaction: p = 0.045; η2 = 0.19), indicating reduced muscle stiffness. No changes in ST shear modulus were observed after either stretching technique. There was no significant correlation between changes in RoM and shear modulus, suggesting that the increase in RoM was predominantly due to changes in stretch tolerance rather than mechanical properties of the muscles. These findings suggest that both SS and PNF stretching can effectively improve hamstring flexibility, but PNF stretching may additionally reduce BF muscle stiffness. The study highlights the importance of considering individual muscle-specific responses to stretching techniques and provides insights into the mechanisms underpinning acute increases in RoM.

Postactivation Performance Enhancement With Maximal Isometric Contraction on Power-Clean Performance Across Multiple Sets.

PURPOSE: This study investigated the postactivation performance-enhancement effect of maximal voluntary isometric contraction (MVIC) at the starting position on power-clean performance over a series of contrast sets. METHODS: Eighteen male (age: 31 [3.7] y, body mass: 76.8 [9.1] kg, height: 175.0 [5.2] cm) and 2 female (age: 27.5 [3.5] y, body mass: 53.3.8 [2.0] kg, height: 158.5 [4.9] cm) resistance-trained individuals performed a contrast postactivation performance-enhancement protocol (isometric contrast training condition [ISO]) consisting of 3 sets of 3 MVICs alternated with 3 power cleans, with an intracontrast rest period of 1 minute. A control protocol consisted of 3 sets of 3 power cleans were performed in a separate session. Barbell velocity during the power clean was measured as an indicator of performance. RESULTS: A significant time effect was observed for both mean velocity (MV; P < .001) and peak velocity (PV; P = .008). Time × group (P = .415-.444) and group (P = .158-.210) effects showed no significant difference for either MV or PV. However, differences in MV and PV between the corresponding sets of ISO and control condition exceeded the minimum worthwhile change, showing a small to moderate effect (MV: d = 0.38-0.50, PV: d = 0.35-0.50) in favor of ISO. There was no significant difference in rating of perceived exertion between conditions (P = .385, d = 0.22). CONCLUSION: Power-clean performance was potentiated after 1 minute of rest following 3 repetitions of MVIC across 3 sets. Furthermore, the ISO protocol did not result in greater perception of exertion. These results indicate that coaches may incorporate MVICs as the postactivation performance-enhancement stimulus during contrast training involving the power-clean exercise.

Acute and Prolonged Effects of 300 sec of Static, Dynamic, and Combined Stretching on Flexibility and Muscle Force.

Static stretching (SS), dynamic stretching (DS), and combined stretching (CS; i.e., DS+SS) are commonly performed as warm-up exercises. However, the stretching method with the greatest effect on flexibility and performance remains unclear. This randomized crossover trial examined acute and prolonged effects of SS, DS, and CS on range of motion (ROM), peak passive torque (PPT), passive stiffness, and isometric and concentric muscle forces. Twenty healthy young men performed 300 sec of active SS, DS, or CS (150-sec SS followed by 150-sec DS and 150-sec DS followed by 150-sec SS) of the right knee flexors on four separate days, in random order. Subsequently, we measured ROM, PPT, and passive stiffness during passive knee extension. We also measured maximum voluntary isometric and concentric knee flexion forces and surface electromyographic activities during force measurements immediately before, immediately after, and 20 and 60 min after stretching. All stretching methods significantly increased ROM and PPT, while significantly decreasing isometric knee flexion force (all p < 0.05). These changes lasted 60 min after all stretching methods; the increases in ROM and PPT and the decreases in isometric muscle force were similar. All stretching methods also significantly decreased passive stiffness immediately after stretching (all p < 0.05). Decreases in passive stiffness tended to be longer after CS than after SS or DS. Concentric muscle force was decreased after SS and CS (all p < 0.05). On the other hand, concentric muscle force was unchanged after DS, while the decreases in surface electromyographic activities during concentric force measurements after all stretching methods were similar. Our results suggest that 300 sec of SS, DS, and CS have different acute and prolonged effects on flexibility and muscle force.

Four minutes of capacitive and resistive electric transfer therapy increased jump performance.

Capacitive and resistive electric transfer (CRET) therapy can improve flexibility and increase muscle activity and may be useful as a warm-up technique. This study examined the effects of short-time CRET on jump performance. Thirty healthy men (age range, 20-40 years) were randomly divided into passive (n = 15) and active (n = 15) warm-up groups. The participants and statisticians were blinded to the participant allocation. The passive warm-up group underwent 4 min of CRET therapy on their posterior lower legs. The active warm-up group performed stretching and jogging for 4 min. Calf muscle temperature and rebound jump (RJ) index were measured before and after the intervention. The mean (± standard deviation) muscle temperature increased by 2.0 ± 0.5°C and 1.4 ± 0.6°C in the passive and active warm-up groups, respectively (p < 0.05). RJ index increased significantly in both groups (p < 0.05). Therefore, passive warm-up using CRET may help avoid energy loss while increasing the muscle temperature in a short time when compared with traditional active warm-up techniques.

Capacitive and resistive electric transfer (CRET) is a device with deep thermal effect. CRET therapy can improve flexibility and increase muscle activity and may be useful as a warm-up technique. This study examined the effects of short-time CRET on jump performance. Thirty healthy men (age range, 20­40 years) were randomly divided into passive (n=15) and active (n=15) warm-up groups. The passive warm-up group underwent 4min of CRET therapy on their calf. The active warm-up group performed stretching and jogging for 4min. Calf muscle temperature and jump performance were measured before and after the intervention. The mean (± standard deviation) muscle temperature increased by 2.0±0.5°C and 1.4±0.6°C in the passive and active warm-up groups, respectively (p<0.05). Jump performance increased significantly in both groups (p<0.05). Therefore, passive warm-up using CRET may help avoid energy loss while increasing the muscle temperature in a short time when compared with traditional active warm-up techniques.

Post-activation performance enhancement does not occur following a large hand-paddles and parachute-resisted warm-up routine in collegiate swimmers.

Our aim was to investigate if using a warm-up routine that included parachute-resisted sprints with large hand-paddles improves 50 m freestyle performance in trained collegiate swimmers. Twelve swimmers (23.9 ± 2.2 years, 179 ± 7 cm, 77.1 ± 10.6 kg) participated in the study and completed two 50-m freestyle races, each preceded by a different warm-up routine, either control (CON) or experimental (EXP). The warm-up routines consisted of 500 m of swimming at self-selected speed, followed by four 10 s sprints with 1 min rest intervals. During EXP, sprints were performed using large hand-paddles and a swimming parachute, while during CON, sprints were performed freely. Performance and technique were assessed during the 50 m freestyle races. We found no significant differences in 25- and 50 m performance times (CON: 12.6 ± 0.8 vs. EXP: 12.5 ± 0.8 s, ES = 0.125; and CON: 26.8 ± 1.6 vs. EXP: 26.7 ± 1.7 s, ES = 0.06, respectively) between the two conditions. Mean stroke length (CON: 2.04 ± 0.21 vs. EXP: 2.02 ± 0.22 m·cycle-1, ES = 0.09), stroke frequency (CON: 55.4 ± 5.3 vs. EXP: 56.3 ± 5.2 cycles s-1, ES = 0.17), and propulsive time (CON: 0.62 ± 0.07 vs. EXP: 0.61 ± 0.06 s, ES = 0.15) were also not different between conditions. It is possible that the CON warm-up routine induced the priming effects that lead to PAPE, or that the EXP warm-up routine primed the athletes further but also induced greater fatigue, resulting in no significant effects on swimming performance. Our findings suggest that parachute-resisted sprints with hand-paddles during warm-up do not enhance 50 m freestyle swimming performance in trained collegiate swimmers. Coaches and practitioners should consider exploring different warm-up protocols to identify what works best for their athletes.