Eccentric Peak Torque Research Articles

Effect of different load during eccentric training with blood flow restriction on muscle size, strength, and performance: A randomized controlled trial✰

Background/Objectivestudies on eccentric training with blood flow restriction (BFR) still has gaps, especially in strength and muscle hypertrophy. Therefore, this study aimed to analyze and compare the effects of six weeks of eccentric training of knee extensors at different load associated or not with BFR on strength, hypertrophy, and performance of knee extensors. Methods61 men, healthy and untrained, performed six weeks of quadriceps muscle eccentric training in isokinetic dynamometer were randomized into four groups: high-load eccentric training with BFR (HLET-BFR), low-load eccentric training with BFR (LLET-BFR), high-load eccentric training (HLET) and low-load eccentric training (LLET). The strength, muscle structure and performance outcomes were evaluated at baseline, after 3 and 6 weeks of training. Resultsfor eccentric peak torque in the first three weeks, HLET was superior to LLET, but similar to LLET-BFR. In the final three weeks, superiority was observed in relation to LLET-BFR; however, there was no difference in relation to HIET-BFR. For the outcomes isometric and concentric peak torque, muscle structure and performance, there were no differences between groups. Conclusioneccentric training led to strengthening of knee extensors and improved performance, but without altering the muscle structure. LLET-BFR promoted gains similar to HLET in the first three weeks of training.

Isokinetic Peak Torque Improvement and Shoulder Muscle Ratios Imbalance Correction After Specific Strength Training on a New Ballistic Throwing Device: A Randomized Controlled Trial.

The aim of this study was to investigate the effects of 8-week ballistic-strength-training program using a validated specific throwing device (ie,Arm/Shoulder Specific Strength Device), on isokinetic shoulders' rotation muscle-torques and ratios as well as range of motion in team handball players. A repeated-measures experimental design with a randomized controlled trial was used. Twenty-six high-level competitive male U-19 team handball players were randomly assigned into training (TG, n = 15) and control (n = 11) groups. The TG undertook a twice a week for 8-week periodized throws program with an individually predetermined optimal load. The program incorporated shackled eccentric and concentric exercises using the Arm/Shoulder Specific Strength Device. Peak torques, functional, and conventional ratios for both arms at different angular velocities (60°·s-1, 180°·s-1, and 300°·s-1) were assessed over time and between groups, using an isokinetic dynamometer. A significant improvement for TG (P < .01; d = 1.13 [moderate]; +20.2%) of the concentric peak torques for dominant arm in external rotation was observed at 300°·s-1. Significant (P < .05-.01) increases were also noted for nondominant arm at the 3 studied angular velocities. In addition, 300°·s-1 eccentric peak torques of the dominant arm and nondominant arm have significantly improved for both external and internal rotations (P < .05; d = .99 [moderate] and d = 1.21 [large]; +15.7% and + 17.9%, respectively) with small changes at the other angular assessed velocities. Posttraining, TG's dominant arm showed significant improvements (P < .05-.01) in functional and conventional ratios at all velocities. Notably, significant differences (P < .05-.01) were observed at 60°·s-1 and across all velocities when comparing the TG with the control group. TG showed significant increase for internal rotation and external rotation shoulder range of motions (P < .05; d = 1.22-1.27 [large]), +5.0% and +7.7%, respectively). The specific 8-week throwing training program on the Arm/Shoulder Specific Strength Device showed significant performance improvements in almost all assessed isokinetic concentric and eccentric peak torques as well as internal and external range of motion increase for both arms while ensuring rotator cuff torque ratios and shoulder mobility in team handball real sport-specific condition.

Cross-Education Effects of Isokinetic Eccentric Plantarflexor Training on Flexibility, Strength, and Muscle-Tendon Mechanics.

Large increases in joint range of motion (ROM) have been reported after eccentric resistance training; however, limited data exist describing the associated mechanisms or potential cross-education effects in the contralateral limb. Therefore, the effects of a 6-wk isokinetic eccentric plantarflexor training program were examined in 26 participants. Before and after the training program, dorsiflexion ROM, plantarflexor strength, and muscle-tendon unit (MTU) morphology and mechanics were measured in control ( n = 13) and experimental ( n = 13) young adult groups. Training consisted of 5 sets of 12 maximal isokinetic eccentric plantarflexor contractions twice weekly on the right limb. Significant ( P < 0.05) increases in dorsiflexion ROM (4.0-9.5°), stretch tolerance (40.3-95.9%), passive elastic energy storage (47.5-161.3%), and isometric (38.1-40.6%) and eccentric (46.7-67.0%) peak plantarflexor torques were detected in both trained and contralateral limbs in the experimental group. Significant increases in gastrocnemius medialis and soleus thickness (5.4-6.1%), gastrocnemius medialis fascicle length (7.6 ± 8.5%), passive plantarflexor MTU stiffness (30.1 ± 35.5%), and Achilles tendon stiffness (5.3 ± 4.9%) were observed in the trained limb only. Significant correlations were detected between the changes in trained and contralateral limbs for dorsiflexion ROM ( r = 0.59) and both isometric ( r = 0.79) and eccentric ( r = 0.73) peak torques. No significant changes in any metric were detected in the control group. Large ROM increases in the trained limb were associated with neurological, mechanical, and structural adaptations, with evidence of a cross-education effect in the contralateral limb being primarily driven by neurological adaptation (stretch tolerance). The large improvements in ROM, muscle size, and strength confirm that isokinetic eccentric training is a highly effective training tool, with potential for use in athletic and clinical populations where MTU function is impaired and current therapies are ineffective.

Immediate effects of kinesiology tape on quadriceps muscle peak torque and knee joint repositioning error in healthy males: Effects of different tensions and directions

BackgroundKnee joint injuries may result from compromised quadriceps muscle strength or diminished knee joint proprioception. The application of Kinesio tape (KT) on the quadriceps muscle from origin to insertion (OTI-KT) or insertion to origin (ITO-KT) could impact knee joint proprioception and quadriceps muscle strength. This study aims to assess the effects of different tensions and directions of KT application on active and passive knee joint repositioning errors (AJRE and PJRE) and peak concentric and eccentric peak torque (CPT and EPT) of the quadriceps muscles in healthy males. MethodTwenty-one healthy males participated in this repeated-measures study design. CPT, EPT, AJRE, and PJRE of the dominant limb were measured by a Biodex dynamometer before and after applying OTI-KT with 0%, 15%, and 40% extra tensions and ITO-KT with 0% tension. ResultsITO-KT demonstrated a significant reduction in AJRE (p < 0.05). Meanwhile, for OTI-KT, a statistically significant difference was observed in both AJRE and PJRE concerning time (F1,126 = 19.74, p < 0.05 for AJRE; F1,126 = 9.96, p < 0.05 for PJRE) and tension (F2,126 = 22.14, p < 0.05 for AJRE; F2,126 = 20.67, p < 0.05 for PJRE). ConclusionApplying KT, especially OTI KT with 40% and 15% extra tension, shows potential in enhancing knee proprioception without immediate impacts on quadriceps muscle torque. This suggests applications in sports performance and knee injury rehabilitation.

Higher Eccentric Hamstring Muscle Fatigue After Participation in a Soccer Match in Young Female Athletes.

Hamstring (HS) strength deficits and imbalances have been identified as risk factors for sustaining anterior cruciate ligament (ACL) injuries and muscular strains, with HS injuries being the most prevalent muscle injuries in soccer athletes. The aim of this study was to investigate HS eccentric strength before and after a soccer match in both male and female soccer athletes. Soccer athletes have changes in eccentric HS strength after a soccer game. Cohort observational study. Level 3. HS eccentric strength (mean and absolute peak torque and total work) was measured in 64 healthy male and female competitive football athletes (14-25 years) with an automatic device during the execution of the Nordic hamstring exercise (NHE) test before and after a 90-minute soccer match. The anterior-knee laxity (AKL) was quantified with an arthrometer. Mean and absolute eccentric HS peak torque decreased by 24.5 N.m (-12.34%; P < 0.01) and 21.9 N.m (-10.08%; P < 0.01) in female athletes, whereas their male peers improved by 19.9 N.m (+9.01%; P = 0.01) and by 20.9 N.m (+8.51%; P = 0.02), respectively. HS total work in female athletes decreased by 831.1 J (P < 0.01) compared with the male athlete reduction of 235.3 J. Both the pre- versus postmatch intersex mean and absolute eccentric HS peak torque changes were significant (P < 0.01), as were the changes in HS total work (P < 0.01). The pre- versus postmatch AKL difference and the dominant versus nondominant limb comparison of the strength parameters were not significantly different. Younger female athletes (14-19 years old) presented a greater decrease in mean and absolute peak HS eccentric strength compared with those in older female athletes and men. HS eccentric strength and work differ based on athlete sex, as measured by the NHE test. Mean peak, absolute peak, and total work showed greater reductions in female athletes than those in their male peers. The subgroup of 14- to 19-year-old female athletes experienced the highest reduction in strength parameters.

The Role of the Nordic Hamstring Curl in the Rehabilitation of Hamstring Injuries: A Narrative Review

Background: Hamstring injuries are common in sports requiring high speed and power, such as soccer, football, and field. Prevention and rehabilitation strategies are essential to address the economic and performance-related consequences of hamstring injuries in sports. A state-of-the-art review provides a comprehensive and up-to-date summary of knowledge on hamstring muscle injuries in athletes. Purpose: To review the literature to verify the effectiveness of Nordic hamstring curls exercise in managing and preventing hamstring injuries during sports activity. Method: Electronic databases used for relevant trials: Google Scholar, Pubmed, Cochrane, NCBI, Science Direct, and CINAHLI. All the articles are taken from 2017 to 2022. On Nordic hamstring curls in sports, players were kept as inclusion criteria. One hundred forty articles were searched, which includes NHE in sports players. After screening, 39 studies were finally included in the review. Result: A total of 39 studies were finally included in the review, of which 17 were Randomized controlled trials, 16 were Systemic Reviews, 2 were Quasi-experimental Studies, and 4 were Observational studies. The hamstring injury rate was substantially lower in groups that included the Nordic Hamstring curl exercise in their daily regime. NHE significantly increases eccentric strength, eccentric peak torque, H: Q ratio, muscle fascicle length, and muscle architecture. Conclusion: There was a significant relation between hamstring injuries and Nordic hamstring curl exercise. NHE is found to be effective in the prevention and rehabilitation of hamstring injuries in athletes. Clinicians should be encouraged to incorporate NHE into their prevention strategies, and players and coaches should be more aware of and encourage the use of NHE. Keywords: Hamstring Injuries, Nordic hamstring exercise, Nordic curl, eccentric strength, injury prevention.

The effects of 6-week home-based static stretching, dynamic stretching, or eccentric exercise interventions on muscle-tendon properties and functional performance in older women

BackgroundJoint inflexibility is acknowledged as a significant contributor to functional limitations in the older adult, with lengthening-type exercises identified as a potential remedial approach. Nevertheless, the responses to eccentric exercise in female older adults have not been extensively studied especially in home-based environment. Here, we aimed to assess the effectiveness of home-based static stretching (ST), dynamic closed-chain stretching (DCS), or eccentric exercise (ECC) interventions on flexibility, musculotendinous architecture, and functional ability in healthy older women. MethodsWe randomly assigned 51 healthy older women (age 65.9 ± 3.4 years) to one of three interventional exercise groups: DCS (N = 17), ECC (N = 17), or ST (N = 17). The training was performed 3 times a week for 6 weeks. The participants’ musculotendinous stiffness, fascicle length, eccentric strength, and functional capacities were measured before the intervention, after 6 weeks of exercise, and at a 1-month follow-up. ResultsThe results showed that all three interventions improved hamstring flexibility and passive ankle dorsiflexion (p < 0.001), with increased biceps femoris and medial gastrocnemius fascicle length (p < 0.01). However, there was no significant change in musculotendinous stiffness. The ECC intervention produced a greater improvement in knee flexor and calf eccentric peak torque (p < 0.05), and gait speed (p = 0.024) than the other two interventions. The changes in flexibility and knee flexor strength remained for up to 4 weeks after detraining. ConclusionIn conclusion, the present study suggests that home-based ECC may be more beneficial in enhancing physical capacities in older women compared with either DCS or SS interventions.

Analysis on the characteristics and relationships of lower limbs strength and power of sailors in different positions and levels.

Hikers and trapeze sailors are two main Olympic groups based on their specific role during sail racing. This study was to analyze the characteristics and relationships of lower limbs strength and power of hikers and trapeze sailors with different levels. Forty-five hikers and trapeze sailors were divided into high-level and low-level groups, respectively. The isokinetic dynamometer was used to measure sailors' lower limbs strength. Concentric and eccentric peak torque (PT) were measured for hamstrings and quadriceps at 60°/s, and isometric knee extensions at 45° knee flexion (0° = full extension). The counter movement jump (CMJ) was performed by Kistler to reflect sailors' lower limbs power. The results showed the hikers had higher quadriceps isometric PT, and male hikers had higher concentric and eccentric PT compared to trapeze sailors (p<0.05). For female sailors, the quadriceps' concentric, eccentric and isometric PT of high-level group were higher than low-level group' (p<0.05). The sailors' conventional and functional H/Q ratio ranged from 0.44 to 0.56 and 0.52 to 0.65, respectively. High-level and low-level groups had no difference in CMJ, which was moderately to strongly correlated with the isokinetic strength (r ranging 0.50-0.81, p<0.01). These findings suggest that long-term training can induce specificity in lower limbs strength of sailors. Hikers have better quadriceps isometric strength compared to trapeze sailors. The quadriceps concentric and eccentric PT can be used as parameters to distinguish between high-level and low-level sailors, but CMJ cannot.

Recovery kinetics following eccentric exercise is volume-dependent

ABSTRACT The present study compared the effect of 75 vs 150 vs 300 intensity-matched eccentric contractions on muscle damage and performance recovery kinetics. Ten healthy males participated in a randomized, cross-over study consisted of 4 experimental trials (ECC75, ECC150, ECC300 and Control – no exercise) with a 4-week washout period in-between. Performance and muscle damage, inflammatory and oxidative stress markers were evaluated at baseline, post-exercise, 24, 48 and 192 hours following each exercise protocol. Concentric and eccentric peak torque decreased similarly in ECC150 and ECC300 during the first 48 h of recovery (p < 0.05) but remained unaffected in ECC75. Countermovement jump indices decreased post-exercise and at 24 h in ECC150 and ECC300, with ECC300 inducing a more pronounced reduction (p < 0.05). Creatine kinase increased until 48 h of recovery in all trials and remained elevated up to 192 h only in ECC300 (p < 0.05). Delayed onset of muscle soreness increased, and knee-joint range of motion decreased in a volume-dependent manner during the first 48 h (p < 0.05). Likewise, a volume-dependent decline of glutathione and a rise of protein carbonyls was observed during the first 48 h of recovery (p < 0.05). Collectively, our results indicate that muscle damage and performance recovery following eccentric exercise is volume dependent, at least in lower limbs.

Hip Abductor and External Rotator Strengths Correlate With Hop Symmetry in Men Athletes 2 Years After Anterior Cruciate Ligament Reconstruction.

Hip muscle strength and hop performance limb symmetries after anterior cruciate ligament reconstruction (ACLR) are not well studied. This study aimed to determine the differences in hip abductors' (ABD) and external rotators' (ER) muscle strength measures between limbs, and the relationship between hip ABD and ER muscle strengths and hop performance limb symmetry indices (LSIs) 2years after ACLR. Cross-sectional study. Forty (level I/II) men athletes 2years after unilateral ACLR completed 4 single-legged hop tests and involved hip ABD and ER strength testing (maximum voluntary isometric contraction [MVIC]; isokinetic peak torque [PKTQ] at 60°, 180°, and 300°/s; and isotonic peak velocity at 75% of their MVICs). Muscle strength measures were normalized to body mass, and hop performances were reported as LSIs. Paired t test was used to determine strength differences between limbs, and the Pearson correlation coefficient was used to assess the relationship between involved hip muscle strength measures and hop performance LSIs. Hip ER-MVIC (involved: 60.26 [12.01], uninvolved: 63.68 [13.17]N·m/kg) and ER eccentric PKTQ at 60°/s (involved: 32.59 [9.28]; uninvolved: 35.73 [10.50]N·m/kg) were significantly different between limbs (P ≤ .018). Single-hop LSI correlated with hip ER-PKTQ at 180°/s (r = .354) and 300°/s (r = .324, P ≤ .041), while triple-hop LSI correlated with hip ER-MVIC (r = .320), concentric ER-PKTQ at 180°/s (r = .355), eccentric ER-PKTQ at 60°/s (r = .314), and hip ABD-PKTQ at 60°/s (r = .364) and 300°/s (r = .336, P ≤ .049). Men athletes demonstrated symmetrical hop performance and hip muscle strengths, except for ER hip's MVIC and isokinetic eccentric peak torque at 60°/s 2years after ACLR. Hop performance LSIs had a few, yet positive moderate relationships with involved hip ABDs and ER strength measures. This may indicate that hip ABD and ER muscle strength measures contribute to athletes' hop performances 2years after ACLR. Post-ACLR rehabilitation programs might incorporate hip muscle strengthening training to improve athletes' functional performances.

Sport-Related Effect on Knee Strength Profile during Puberty: Basketball vs. Soccer.

The present study examined and compared the isokinetic peak torque and the reciprocal ratios of the knee joint between young basketball and soccer players. An amount of 100 soccer and 100 basketball players took part in this study and were separated into five equal groups (n = 20), according to their chronological age (12, 13, 14, 15, and 16 years old). The absolute concentric (CON) and eccentric (ECC) peak torque of the knee flexor and extensor muscles (at 60°/s, 180°/s) were assessed using a Cybex Norm dynamometer, and the relative peak torque (per unit of body mass), as well as the conventional (CON/CON; ECC/ECC) and functional (CON/ECC; ECC/CON) ratios, were calculated. Data analysis indicated that the basketball players had higher absolute peak torque values than the soccer players throughout their developmental ages (p < 0.05). When the isokinetic peak torque values were normalized relative to body mass, no differences were observed between basketball and soccer players in any age group (p > 0.05). Additionally, no differences were observed in conventional and functional ratios between soccer and basketball players (p > 0.05). In conclusion, it appears that, during developmental ages (12-16 years old), the isokinetic strength profile (independent of body mass affecting absolute values) of knee extensor and flexor muscles develops similarly in basketball and soccer players.

Effects of eccentric-emphasized leg curl intervention on muscle strength imbalance markers in professional soccer players during pre-season

BackgroundThe effects of strength training on muscle strength imbalance are unclear in professional soccer players. As a result, this study examined the effects of an 8-week strength training program comprising eccentric-emphasized prone leg curl adjusted according to the individual strength imbalance status. MethodsTen professional soccer players (26.0 ± 3.6 yrs) participated in the study. Players who had a ≥ 10% contralateral imbalance in knee flexors eccentric peak torque (n = 6) performed two additional repetitions per set in the low-strength limb (high-volume, HV) compared to the high-strength limb (low-volume, LV). Isokinetic concentric knee extension and concentric and eccentric knee flexion peak torque (PT) and derived contralateral imbalances and conventional and functional hamstring-to-quadriceps ratios (H:Q) were assessed at baseline and after 8 weeks. Differences at baseline were assessed using paired-sample T-tests, and a two-way (limb x time) repeated measures analysis of covariance (ANCOVA) for changes over time. ResultsA significant improvement in the eccentric knee flexion PT was observed in both limbs after 8 weeks (P < 0.05), with greater effects observed in the HV limb (25.0 N m, 95% CI: 15.1–34.9 N m). Significant decreases were also observed in the contralateral imbalances from concentric knee extension and flexion and eccentric knee flexion PT (P < 0.05). Differences were not observed in concentric knee extension and flexion PT (P > 0.05). ConclusionsA short-term eccentric-emphasized leg curl intervention adjusted by the initial knee flexors eccentric strength was an efficient method to improve knee flexors strength imbalance in professional soccer players.

The effect of different exercise intensities on knee and ankle joints' torque and functional mobility in children with Down Syndrome

The aim of this study was to compare the effect of mild and moderate exercise intensity on selected knee and ankle isokinetic parameters and functional mobility in children with Down Syndrome (DS), in order to find the appropriate exercise intensity that is beneficial for them. A clinical controlled trial was conducted on thirty-four male children with DS, aged between eight and twelve years, which were randomly divided into two groups (Group 1 and Group 2). The first group (Group 1) received mild-intensity treadmill aerobic exercises [T-AE] and the second group (Group 2) received moderate-intensity T-AE, three sessions weekly for three months. The timed up and go (TUG) test was utilized to evaluate the functional mobility while the peak eccentric torque of knee extensors and ankle plantar flexors of the dominant leg was evaluated by isokinetic dynamometry. IBM SPSS Program (version 20) was utilized to conduct the statistical analysis. There was a statistically significant improvement in the three variables after intervention with the moderate-intensity program (p&lt;0.05), while the improvement was not statistically significant after intervention with the mild-intensity program (p&gt;0.05). A moderate-intensity exercise program is an appropriate and beneficial intervention and should be considered as a part of rehabilitation programs for DS children.

Effects of modified hybrid resistance training on concentric quadriceps femoris peak torque and eccentric hamstring peak torque in untrained healthy subjects

Background: Leg muscular strength may decline as a result of decreased mechanical stress on the muscles brought on by the COVID-19 pandemic's physical inactivity. The hybrid training method uses the force generated by an electrically stimulated antagonist muscle to resist a voluntarily contracting agonist muscle. Due to the lack of external resistance or stability equipment, this exercise may be a good option for strengthening workouts during a pandemic. Modifications were made using conventional stimulation tools because the hybrid training system was difficult to replicate. The study's objective was to analyze the effect of modified hybrid resistance training on concentric quadriceps femoris peak torque (QCON) and eccentric hamstring peak torque (HECC). Methods: The study was conducted at the Medical Rehabilitation Installation of Dr. Soetomo General Academic Hospital Surabaya. The subjects were 30 untrained healthy men aged 18-40 years divided into the treatment group, which received modified hybrid resistance training and the control group, which received Russian protocol neuromuscular electrical stimulation 3 times per week for 4 weeks. Due to COVID-19 infection, four participants couldn’t continue in intervention. Statistical tests were carried out on subjects that were able to complete the study (treatment: 13, control:13). Results: There were increases in 60o/sec QCON (p-value 0.005) and 120o/sec QCON (p-value 0.001) in the non-dominant leg in the treatment group. There were increases in 60o/sec QCON (p-value 0.043), 120o/sec QCON (p-value 0.014), and 120o/sec HECC (p-value 0.043) in the non-dominant leg in the control group. There is a significant difference in non-dominant 120o/sec ΔQCON between the two groups (p-value 0.036). Conclusion: There was a more significant increase in QCON in the modified hybrid training exercises group compared to the Russian stimulation group in untrained healthy subjects.

Skeletal muscle and erythrocyte redox status is associated with dietary cysteine intake and physical fitness in healthy young physically active men.

To investigate the association between redox status in erythrocytes and skeletal muscle with dietary nutrient intake and markers of physical fitness and habitual physical activity (PA). Forty-five young physically active men were assessed for body composition, dietary nutrient intake, muscle strength, cardiorespiratory capacity and habitual PA. Blood and muscle samples were collected to estimate selected redox biomarkers. Partial correlation analysis was used to evaluate the independent relationship of each factor with redox biomarkers. Dietary cysteine intake was positively correlated (p < 0.001) with both erythrocyte (r = 0.697) and muscle GSH (0.654, p < 0.001), erythrocyte reduced/oxidized glutathione ratio (GSH/GSSG) (r = 0.530, p = 0.001) and glutathione reductase (GR) activity (r = 0.352, p = 0.030) and inversely correlated with erythrocyte protein carbonyls (PC) levels (r = -0.325; p = 0.046). Knee extensors eccentric peak torque was positively correlated with GR activity (r = 0.355; p = 0.031) while, one-repetition maximum in back squat exercise was positively correlated with erythrocyte GSH/GSSG ratio (r = 0.401; p = 0.014) and inversely correlated with erythrocyte GSSG and PC (r = -0.441, p = 0.006; r = -0.413, p = 0.011 respectively). Glutathione peroxidase (GPx) activity was positively correlated with step count (r = 0.520; p < 0.001), light (r = 0.406; p = 0.008), moderate (r = 0.417; p = 0.006), moderate-to-vigorous (r = 0.475; p = 0.001), vigorous (r = 0.352; p = 0.022) and very vigorous (r = 0.326; p = 0.035) PA. Muscle GSSG inversely correlated with light PA (r = -0.353; p = 0.022). These results indicate that dietary cysteine intake may be a critical element for the regulation of glutathione metabolism and redox status in two different tissues pinpointing the independent significance of cysteine for optimal redox regulation. Musculoskeletal fitness and PA levels may be predictors of skeletal muscle, but not erythrocyte, antioxidant capacity. Registry: ClinicalTrials.gov, identifier: NCT03711838, date of registration: October 19, 2018.

Effect of Thermotherapies Associated with Hamstring Stretching in Peak Torque: Randomized Clinical Trial

Background: Stretching is an effective strategy used mainly to reduce muscle stiffness, and increase both flexibility and Range of Motion. Aim: To compare the effects of different thermotherapy modalities associated with static stretching on peak torque (PT) of knee flexor muscles. Methods: This study compared a sample of 34 healthy men, aged between 20 and 30 years, with active knee range of motion (ROM) ≤160 degrees. They were subjected to three sessions of static stretching of the hamstrings, either with or without a thermotherapy modality. The order of interventions was randomized for one of the groups: isolated stretching (IS), stretching with heat (SH), and stretching with cold (SC). The concentric and eccentric PTs were assessed pre and post-intervention. Results: In the comparison of PT among different measures, there was a significant decrease in eccentric and concentric PT of knee flexor muscles in IS, in eccentric PT of knee flexor muscles in SH, and in eccentric and concentric PT of knee flexors in SC groups. Conclusion: Regardless of the use of thermotherapy, one single session of static stretching resulted in decreased PT of knee flexor muscles. This is probably due to the effects of stretching, such as the immediate change of the elastic component of the muscle-tendon unit, which leads to a deficit in acute force production.

A study on isokinetic knee flexor and extensor peak torque during concentric and eccentric contraction at different angular velocities in junior India male volleyball players

This article aims to study the isokinetic knee flexor and extensor peak torque during concentric and eccentric contraction at different angular velocities and further understand the various muscle group characteristics that may lead to injury in athletes. The isokinetic concentric and eccentric strength measurements of twenty junior India volleyball players with an average age of 18.05 (± 0.76) years were used in this study. Humac Norm Isokinetic Dynamometer measures isokinetic concentric and eccentric peak torque (Nm) of knee extension, knee flexion, and knee flexion to extension ratio for both legs at angular velocity 60°/s, 90°/s, and 120°/s. The sample comparison for eccentric and concentric data is performed, and significant (p &lt; 0.01) differences between the left and right legs at different angular velocities are observed.

Effects of 6 weeks in-season flywheel squat resistance training on strength, vertical jump, change of direction and sprint performance in professional female soccer players.

Flywheel resistance training devices (FRTD) is shown effective in improving strength, sprinting, jumping and changes of direction (COD) performance in male soccer players, however, this is not elucidated in female soccer players. We aimed to assess the effect of FRTD on these physical abilities in females soccer players. 24 professional female soccer players (age: 20.4 ± 2.6 years) were randomly assigned to a flywheel training group (FWTG) that trained twice a week for 6 weeks on a rotary inertia device with an initial volume of 3 sets of 6 repetitions and an inertia of 0,025 kg · m-2, increasing intensity and volume or a control group (CG) that did not performed any additional resistance training program. Concentric peak torque of the knee extensors (CONEXT) and flexors (CONFLEX), eccentric peak torque of the knee extensors (ECCEXT) and flexors (ECCFLEX) at 60° · s-1 on an isokinetic dynamometer, countermovement jump (CMJ) height, COD and 30-metres sprint were assessed. Significant time by group interactions were found in CONEXT (p = 0.002; η²p = 0.425), CONFLEX (p = 0.037; η²p = 0.22), ECCEXT (p = 0.002; η²p = 0.43) and ECCFLEX (p = 0.008; η²p = 0.334). No time by group effect was found in CMJ (p = 0.061; η²p = 0.182), COD (p = 0.067; η²p = 0.184) or sprint (p = 0.926; η²p = 4.979 · e-4). In conclusion, 6 weeks of flywheel squat training improved strength (especially eccentric strength) but not soccer-specific abilities such as jumping, changing of direction or sprinting in professional soccer players.

Effects of sprint versus strength training on risk factors for hamstring injury in football players.

This study aimed to compare the effects of in-season sprint training vs. Nordic hamstring exercise (NHE) training on risk factors for hamstring strain injuries (HSI). Eighteen male university football players (20.9±2.5 years; 181±7 cm; 75.8±9.1 kg; 15.2±3.5% of body fat) were randomly allocated to a sprint group or NHE group. They completed baseline isokinetic strength and sprint mechanics assessments prior to their assigned intervention performed twice weekly for 4-weeks, before post-testing. A mixed design ANOVA with repeated measures assessed time, group and interaction effects for all risk factors. There were significant increases in hamstring eccentric peak torque at 60°·s-1 (+8% - 9.9%), the torque produced at 20° (+15%) and 10° (+21% - 31%), as well as a rightward shift in angle of peak torque towards knee extension (-27% - -36%) in both groups (P<0.05). We also observed a significant increase (+24.5%) in hamstring eccentric peak torque at 180°·s-1 in the strength group only and significant improvements (+29.4%) in the rate of torque development of the dominant leg at 60°·s-1 in the sprint group only (P<0.05). No significant effect was noted on sprint performance or sprint mechanics (P>0.05). These findings suggest that both training programs can be effective to mitigate the risk of HSI, but through different mechanisms.

Effect of kinesiotaping on subtalar evertor and invertor muscle strength in healthy individuals

IntroductionTo date, no study examined the effect of ankle kinesiotaping on eccentric versus concentric subtalar evertor and invertor strength nor compared its effect between evertors and invertors. This study examined the effect of kinesiotaping on peak subtalar evertor and invertor eccentric and concentric torques assessed at 120º/sec. Eccentric versus concentric torque in both muscle groups as well as evertor versus invertor torque at both modes of muscle contraction were examined.MethodsA group of 30 healthy individuals (24 males and 6 females) with mean age 21 ± 2.73 years, height 1.73 ± 0.08 m, and weight 75 ± 6.20 kg were tested. They were randomly tested with kinesiotape use and without. The kinesiotape was applied on the tibialis anterior, tibialis posterior, peroneus longus and peroneus brevis muscles. The peak torques were assessed using a Biodex isokinetic dynamometer.Results2×2×2 Repeated Measure ANOVA revealed that the peak torque was significantly higher with kinesiotape use compared with no tape for both eccentric and concentric evertors, and eccentric invertors (p ≤ 0.009). The eccentric peak torque was significantly higher than the concentric for both evertors and invertors with kinesiotape use, and evertors with no tape (p ≤ 0.001). Finally, the invertor concentric torque was significantly higher than the evertor torque with no tape use (p &lt; 0.001).ConclusionsAnkle kinesiotaping improves both evertor and invertor torques with the eccentric torque being significantly improved compared with the concentric. No significant effect on evertors versus invertors was found. This suggests kinesiotape use for managing musculoskeletal disorders caused by impaired subtalar muscle strength as lateral ankle sprains.