Peak Torque Measurements Research Articles

The effects of different post-activation potentiation strategies on the performance of elite female track cyclists in position 1 of team sprint

The study aimed to optimise post-activation potentiation (PAP) strategies for Rider 1 in elite team sprints to improve performance over 250 m (opening lap), with a focus on female cyclists. Eight national-level track cyclists participated in this study, undergoing four sets of activation strategies: control (CON), dynamic high inertia (DYN, 4 × 4 pedal strokes), isometric contraction (ISO, 4 × 4 s, 4 angles), and back squat activation (BSQ, 4 × 4 rep, 80%1RM). The tests were divided into pre-activation and post-activation phases, including measurements at 4 min, 8 min, and 12 min after activation. The tests included a 250 m time trial (TT) and segment timing, with measurements of peak torque, peak power, average power, and cadence. The mean cadence, torque, and power for the first 62.5 m of pedal revolutions were collected. Paired-sample t-tests were used to assess activation differences. Multiple group comparisons were conducted using analysis of variance (ANOVA). The Bonferroni correction was used to control Type I errors. For significant activation strategies, linear or non-linear regression was applied to extrapolate the torque-cadence and power-cadence profiles, and the parameter differences were examined to investigate profile changes. Cohen’s d and Cohen’s f were used as effect sizes. After DYN activation, the 250 m TT significantly improved (p = 0.018), primarily through a reduction in the 62.5 m time (p = 0.006) and an increase in peak torque (p = 0.018). After 12 min of ISO activation, the 250 m TT showed a large effect but did not reach the significance level under Bonferroni correction (p = 0.135, d = 0.860), with a notable reduction in the 62.5 m time (p = 0.003). PAP can be strategically employed to enhance the performance of elite female Rider 1 in team sprints.

Change in sprint cycling torque is not associated with change in isometric force following six weeks of sprint cycling and resistance training in strength-trained novice cyclists.

Strong relationships exist between sprint cycling torque and isometric mid-thigh pull (IMTP) force production at one timepoint; however, the relationships between the changes in these measures following a training period are not well understood. Accordingly, this study examined the relationships in the changes of sprint cycling torque and IMTP force following six-weeks of sprint cycling and resistance training performed by strength-trained novice cyclists (n=14). Cycling power, cadence, torque and IMTP force (Peak force [PF]/torque, average and peak rate of force/torque development [RFD/RTD], and RFD/RTD from 0 to 100ms and 0-200ms) were assessed before and after training. Training consisted of three resistance and three sprint cycling sessions per week. Training resulted in improvements in IMTP PF (13.1%) andRFD measures (23.7%-32.5%), cycling absolute (10.7%) and relative (10.5%) peak power, peak torque (11.7%) and RTD measures (27.9%-56.7%). Strong-to-very strong relationships were observed between cycling torque and IMTP force measures pre- (r=0.57-0.84; p<0.05) and post-training (r=0.63-0.87; p<0.05), but no relationship (p>0.05) existed between training-induced changes in cycling torque and IMTP force. Divergent training-induced changes in sprint cycling torque and IMTP force indicate that these measures assess distinct neuromuscular attributes. Training-induced changes in IMTP force are not indicative of training-induced changes in sprint cycling torque.

Isokinetic Ankle Inversion and Eversion Muscle Strength in Korean Men’s Professional Basketball Players

PURPOSE: In this study, the isokinetic strength of ankle inversion and eversion in Korean professional basketball players (KBL) was assessed, distinguishing between their dominant and non-dominant legs, as well as across different positions.METHODS: A meticulously designed study was conducted involving 25 KBL players (12 guards, 11 forwards, and 2 centers) with an average age of 27.8 ± 5.3 years. The CSMI Norm isokinetic dynamometer, a highly accurate instrument, was used to measure bilateral isokinetic concentric strength at 60°·s-¹ and 150°·s-¹. The study measured peak torque (Nm), body mass normalized peak torque (Nm·kg-¹), bilateral strength asymmetry, and the eversion-to-inversion strength ratio in both dominant and non-dominant legs.RESULTS: Peak torques, normalized peak torques, and eversion-to-inversion strength ratios were not significantly different between the dominant and non-dominant legs at the two angular speeds. There was also less than a 10% asymmetry in strength between the two legs. However, a position-specific analysis revealed that guards had a significantly higher normalized peak torque (0.35 vs. 0.30 Nm·kg-1, p = .048) for ankle inversion of the dominant leg at 150°·s-¹ compared to forwards.CONCLUSIONS: The results suggest that healthy KBL players exhibit symmetrical ankle inversion and eversion muscle strength between their dominant and non-dominant sides, with possible positional differences in strength. These findings serve as a reference for the assessment of inversion and eversion strength in basketball players.

Lessons for future clinical trials in adults with Becker muscular dystrophy: Disease progression detected by muscle magnetic resonance imaging, clinical and patient-reported outcome measures.

Because Becker muscular dystrophy (BMD) is a heterogeneous disease and only few studies have evaluated adult patients, it is currently still unclear which outcome measures should be used in future clinical trials. Muscle magnetic resonance imaging, patient-reported outcome measures and a wide range of clinical outcome measures, including motor function, muscle strength and timed-function tests, were evaluated in 21 adults with BMD at baseline and at 9 and 18 months of follow-up. Proton density fat fraction increased significantly in 10/17 thigh muscles after 9 months, and in all thigh and lower leg muscles after 18 months. The 32-item Motor Function Measurement (MFM-32) scale (-1.3%, p = 0.017), North Star Ambulatory Assessment (-1.3 points, p = 0.010) and patient-reported activity limitations scale (-0.3 logits, p = 0.018) deteriorated significantly after 9 months. The 6-min walk distance (-28.7 m, p = 0.042), 10-m walking test (-0.1 m/s, p = 0.032), time to climb four stairs test (-0.03 m/s, p = 0.028) and Biodex peak torque measurements of quadriceps (-4.6 N m, p = 0.014) and hamstrings (-5.0 N m, p = 0.019) additionally deteriorated significantly after 18 months. At this timepoint, domain 1 of the MFM-32 was the only clinical outcome measure with a large sensitivity to change (standardized response mean 1.15). It is concluded that proton density fat fraction imaging of entire thigh muscles is a sensitive outcome measure to track progressive muscle fat replacement in patients with BMD, already after 9 months of follow-up. Finally, significant changes are reported in a wide range of clinical and patient-reported outcome measures, of which the MFM-32 appeared to be the most sensitive to change in adults with BMD.

Association of cartilage metabolism biomarkers and 25(OH)D levels with muscle biomechanical functions in professional rowers and canoeists

The purpose of the study was to assess the association of cartilage metabolism biomarkers and vitamin D metabolite levels with muscle biomechanical functions in professional rowers and canoeists. The serum levels of aggrecan, cartilage oligomeric matrix protein (COMP), and 25-hydroxyvitamin D (25(OH)D) were determined in elite male sweep-oar rowers (n = 24) and canoeists (n = 15). This was followed by a biomechanical study consisting in isometric measurement of peak torque (PT) of muscles involved in the rowing cycle in the athletes. There were found significant correlations of COMP with the ratio of trunk PT flexor to extensor (p < 0.05) and 25(OH)D with trunk PT—left rotators (p < 0.05), knee joints PT—left and right flexor (p ≤ 0.01), ratio of knee joint PT—right flexor to knee joint PT—right extensor (p < 0.05) in rowers and aggreccan with elbow joint PT of the right flexor (p ≤ 0.01) and extensor (p = 0.05) in canoeists. The correlations of COMP and aggrecan levels with PT of the muscle groups studied in rowers and canoeists indicate the importance of stabilizing the muscular system in cartilage metabolism. The relationship between 25(OH)D status and biomechanical parameters confirm that vitamin D plays an important role in maintaining skeletal muscle health.

Assessment of Isokinetics and Range of Motion of the Shoulder in Patients after Reverse Shoulder Arthroplasty in the Late Follow-Up Period

(1) Background: The aim of the study was to evaluate the peak torque (PT) in isokinetic conditions and the range of motion of the shoulder joint in patients after reverse total shoulder arthroplasty in the late treatment period. (2) Methods: The study included fifteen patients aged 60–70 years (13 women and 2 men). The comparison group consisted of 15 healthy subjects (12 women and 3 men) aged 60–69 years. The study included measurement of peak torque (PT) and the range of motion of the shoulder joint, assessed using the Biodex System 4 Pro set, and an electronic goniometer. We conducted tests at two different angular velocities (60°/s and 90°/s), taking into account the operated and non-operated limb and comparing the results to healthy subjects. The average time from surgery to functional examination was 16 months. (3) Results: The non-operated limb generated significantly higher PT values than the operated limb (p &lt; 0.001). The healthy limb of patients from the comparison group generated significantly higher PT values than the operated limb of patients from the study group (p &lt; 0.001). A significant improvement (p &lt; 0.001) in the range of motion in the operated limb was achieved after rTSA. (4) Conclusions: In patients 18 months after the rTSA, the non-operated upper limb has significantly greater muscle strength in flexion/extension and abduction/adduction movements compared to the operated limb. The non-operated limb also has a significantly greater range of motion compared to the operated limb.

Effect of Spinal Correction Surgery on Lower Limb Strength in Idiopathic Adolescent Scoliosis.

Objectives To analyze the lower limb strength in both untreated and surgically treated adolescent idiopathic scoliosis (AIS) patients and examine its correlation with the distance covered in a six-minute walking test (6MWT). Methods A total of 88 participants (n = 30 pre-surgery AIS patients, n = 30 post-surgical AIS patients, and n = 28 control) underwent a 6MWT and a muscle strength assessment. The lower limb strength was measured at the knee joint using the knee extension (KE) and knee flexion (KF) peak torque (PT) measurements. Results The control group covered a greater distance in the TC6 compared to both the pre-surgical (534 ± 67 m) and post-surgical (541 ± 69 m) groups, with a distance of 612 ± 70 m (p < 0.001). No differences were observed in KE PT (pre: 2.1 ± 0.63, post: 2.1 ± 0.7, control: 2.2 ± 0.7 Nm.kg -1 , p = 0.67) or KF PT (pre: 1.0 ± 0.3, post: 1.1 ± 0.3, control: 1.1 ± 0.5 Nm.kg -1 , p = 0.46). A moderate positive correlation was observed between KE PT and 6MWT distance (r = 0.53, p < 0.001), as well as a low positive correlation for KF PT (r = 0.37, p = 0.003) with 6MWT distance. Conclusion This study highlights the importance of lower limb maximal strength in the functionality of AIS patients. Our findings suggest that exercise programs aimed at enhancing lower limb strength, especially the KE, could improve the walking capacity of AIS patients. These results provide useful information for designing purposeful exercise programs for AIS patients with walking deficits.

A comparison between hypertonic dextrose prolotherapy and conventional physiotherapy in patients with knee osteoarthritis.

The aim of the present study was to compare the efficacy of hypertonic dextrose prolotherapy (HDP) with conventional physiotherapy (CPT) in improving symptoms in females with knee osteoarthritis (OA). The present study included 60 patients with a diagnosis of knee OA. The patients were randomly assigned to the HDP (n=30) and CPT (n=30) groups. The patients in the HDP group were treated with a dextrose injection into the knee joint (25% dextrose) and around the knee (15% dextrose) in two sessions for 1 month, while those in the CPT group received a hot pack, transcutaneous electrical nerve stimulation and therapeutic ultrasound in five sessions a week for 4 weeks. Prior to commencing the treatment, and at 1 and 3 months post-treatment, all the patients were evaluated using the visual analog scale (VAS), Western Ontario and McMaster Osteoarthritis Index (WOMAC), the goniometric measurement of active knee range of motion (ROM), a 50-m walking test and isokinetic knee muscle strength measurements. There were no statistically significant differences between the two groups as regards the demographic characteristics at pre-treatment (P>0.05). However, at 1 and 3 months post-treatment, the scores of all the outcome parameters were significantly improved in the HDP group compared with the CPT group (P<0.05 for all). In both groups, a significant improvement was observed in the VAS scores, WOMAC total values and ROM following the treatments, with the greatest improvement observed in the HDP group (P<0.001). The isokinetic quadriceps peak torque measurements were increased in both groups following treatment. All the scores exhibited a statistically significant improvement in the HDP group at both 1 and 3 months post-treatment. On the whole, the results of the present study demonstrate that both HDP and CPT are effective treatment modalities to relieve pain, and increase functionality and strength in patients with knee OA. However, greater improvements in pain and functionality can be achieved with prolotherapy.

Isokinetic Dynamometer Leg Extensor Peak Torque Measurement: A Time-Delayed Reliability and Score Selection Analysis Study.

The reliability of isokinetic peak torque (PT) has been reported mostly using a short-term (<~10 day) inter-trial testing time frame. However, many studies and programs utilize a long-term (several weeks to months) inter-trial testing period. Additionally, the methods by which the PT value is selected and reported from a multiple rep testing scheme have not been well investigated for both reliability and PT absolute performance comparisons. The purpose of this study was to investigate the long-term reliability of isokinetic and isometric PT of the leg extensors with an emphasis on the differences among several PT score selection methods. Thirteen men and women (age = 19.5 years) underwent two testing trials separated by 28.8 (±1.8) days. Testing included maximal voluntary contractions of three sets of three reps for two isokinetic contraction conditions of 60 (Isok60) and 240 (Isok240) deg/s velocities, and three sets of one rep of isometric contractions for the leg extensors. The PT score was derived from seven different methods (see text for descriptions). Reliability as assessed from intraclass correlation coefficients (ICCs) varied widely across contraction conditions and PT score selection parameters. The Isok60 velocity overall had lower reliability (ICCs = 0.48-0.81) than Isok240 (0.77-0.87) across the conditions whereas the isometric PT variables showed moderate reliability (0.71-0.73). Overall the set 1 PT score selection parameters were generally lower (p ≤ 0.05) than those that involved sets two and three. Systematic error (p ≤ 0.05) was shown for 6 out of the 17 PT selection variables. On a subjective interpretation basis, when taking everything into account the best overall combination of time/trial efficiency, reliability, best/highest PT score parameter, and reduced risk of systematic bias appears to be the PT variable that uses the average of the highest two reps of the first two sets of three reps-i.e., averaging the highest two values of the six total reps from the first two sets.

Do Different Approaches Make a Difference in Isokinetic Performance in Elderly Patients With Femoral Neck Fracture Who Underwent Bipolar Endoprosthesis?

Background There are ongoing doubts about the effects of the commonly used anterolateral approach (ALA) and posterolateral approach (PLA) for bipolar hemiarthroplasty (BHA) on hip muscle strength after surgery. In this study, it was aimed to evaluate the isokinetic performance of the operated and non-operated hips in patients with femoral neck fractures who underwent BHA with PLA or ALA and to compare the isokinetic performance of the hips and functional results between the two approaches. Materials and methods Forty-one patients who underwent unilateral BHA with PLA or ALA for femoral neck fracture between February 2019 and December 2020 were enrolled. The isokinetic performance of the flexor, extensor, and abductor muscles of the operated and non-operated hips were evaluated by measuring peak torque, total work, and average power. Functional status was assessed using Harris Hip Score and Short Form 36. Results The patients were divided into two groups; those operated with PLA (n=22) and with ALA (n=19). The groups had similar demographic and clinical characteristics. All isokinetic parameters of the operated hips did not differ between the groups (all p>0.05). In both groups, all isokinetic parameters were significantly lower in the operated hips than in the non-operated hips. Conclusion Although there are debates about potential extensor muscle injury with PLA and potential abductor muscle injury with ALA, this study showed that functional results and the isokinetic performance of both approaches were not different.

Angle-Specific Isokinetic Shoulder Rotational Strength Can be Reliably Assessed in Collision and Contact Athletes.

An increased understanding of rotational strength as a potential prognostic factor for injury in contact and collision athletes may be important in planning return to sport. The aim of this study was to (1)determine the test-retest reliability of clinically relevant, angle-specific rotational and peak torque measurements in a cohort of uninjured collision and contact athletes; (2)develop a normal descriptive profile of angle-specific rotational torque measurements in the same cohort; and (3)examine the effects of direction and joint angle on shoulder rotational strength interlimb asymmetries. Twenty-three collision and contact athletes were recruited for the interday reliability substudy and 47 athletes were recruited for the remaining substudies. We used intraclass correlation coefficients with 95% confidence intervals to quantify interday reliability of all variables. We used a 2-way repeated-measures analysis of variance to analyze differences in absolute interlimb asymmetries. Interday reliability for the isokinetic strength variables was good to excellent (0.78-0.90) on the dominant side and moderate to good (0.63-0.86) on the nondominant side. Maximum angle-specific torque (as well as peak torque) can be measured reliably in internally and externally rotated positions. A normal profile of clinically relevant, angle-specific shoulder rotational torque measurements for collision and contact athletes has been established which provides a reference when assessing shoulder strength in this population.

Core muscle strength can be reliably measured using a novel isokinetic device: An intra-observer study.

BACKGROUND: Core strength is an important aspect of physical fitness. A dynamometer was developed to measure isokinetic core muscle strength in multiple planes of motion. Establishing the reliability is needed before it can be used in practice.OBJECTIVE: Examine the intra-observer reliability of a trunk isokinetic dynamometer.METHODS: 31 participants were recruited. Tests were performed twice with an interval of 5–9 days by the same observer. Testing included rotation, flexion/extension and lateral flexion at speeds of 90/s and 60/s. The main outcome measure was peak torque (PT). The secondary outcomes included peak torque angle (PTA), time to peak torque (TTPT) and compensatory torques (CompTQ). The intra-observer reliability was investigated using intraclass correlation coefficients (ICC).RESULTS:Peak torque reliability was good to excellent (ICC 0.70–0.91), whereas the reliability of the PTA (ICC 0.04–0.56) and TTPT (ICC 0.01–0.68) were poor to moderate. CompTQ reliability was moderate to good (ICC 0.20–0.88).CONCLUSIONS: The intra-observer reliability of the isokinetic measurement of core strength peak torque was good. The secondary outcomes peak torque angle and time to peak torque were less reliable and the compensatory torques showed moderate to good reliability. This isokinetic dynamometer could have useful applications in the field of sports medicine and rehabilitation.

Can phase angle from bioelectrical impedance analysis associate with neuromuscular properties of the knee extensors?

Maintenance and improvement of neuromuscular functions is crucial for everyone regardless of age. An easy way to assess neuromuscular properties without muscle contraction is useful especially for those who cannot perform strenuous muscular force production, such as older adults and patients with orthopedic or cognitive disorders. Bioelectrical impedance analysis (BIA) can assess body electrical properties e.g., phase angle (PhA) which is regarded as muscle quantity/quality index. The purpose of this study was to investigate associations of PhA with neuromuscular properties of the knee extensors in 55 young (n = 23) and older (n = 32) adults. The values of PhA of the right thigh and whole-body were determined with BIA at 50 kHz. The participants performed 4-s maximal voluntary isometric contraction (MVIC) to measure peak torque (PTMVIC), and 1-s brief MVIC to assess rate of torque development (RTD) over the time interval of 0–200 ms. As markers of physiological mechanisms of muscle force production, twitch contractile properties (peak twitch torque, rate of twitch torque development, and time-to-peak twitch torque) of the knee extensors obtained by femoral nerve electrical stimulation, and muscle activity assessed as root mean square values of electromyographic activity (EMG-RMS) during PTMVIC and RTD measurements were measured. Thigh and whole-body PhA significantly correlated with PTMVIC (r ≥ 0.555, p < 0.001) and electrically evoked twitch parameters (peak twitch torque, rate of twitch torque development, and time-to-peak twitch torque; |r| ≥ 0.420, p ≤ 0.001), but not RTD (r ≤ 0.237, p ≥ 0.081) or EMG-RMSs (|r| ≤ 0.214, p ≥ 0.117). Stepwise multiple linear regression analysis revealed that thigh PhA was selected as a significant variable to predict PTMVIC but not RTD. Whole-body PhA was not selected as a significant variable to predict PTMVIC or RTD. In conclusion, both thigh and whole-body PhA can associate with maximal voluntary muscle strength of the knee extensors, and this association may be due to intrinsic contractile properties but not neural aspects. Regarding prediction of the knee extensor strength, thigh PhA is preferable as the predictor rather than whole-body PhA which is used as a widely acknowledged indicator of sarcopenia.

Effect of Leg Half-Squat Training With Blood Flow Restriction Under Different External Loads on Strength and Vertical Jumping Performance in Well-Trained Volleyball Players.

PurposeTo examine the effect of blood flow restriction resistance training under different external loads on the muscle strength and vertical jumping performance in volleyball players.Methods18 well-trained collegiate male volleyball players were randomly divided into 3 groups: high-load resistance training group (HL-RT, 70% 1RM, n = 6), low-load blood flow restriction resistance training group (LL-BFR-RT, 30% 1RM, 50% arterial occlusion, n = 6), and high-load blood flow restriction resistance training group (HL-BFR-RT, 70% 1RM, 50% arterial occlusion, n = 6). Participants performed leg half-squat exercise 3 times per week for 8 weeks. Measurements of Isokinetic peak torque of knee extension and flexion, 1RM leg half-squat, squat jump, and 3 footed take-off were obtained before and after training. A two-way repeated-measures analysis of variance was used to examine differences among the 3 groups and between the 2 testing time (pre-test vs post-test).Results(1) The HL-RT group was significantly greater in muscle strength than that in the LL-BFR-RT group (P < .05), but no improvement in vertical jumping performance (P >.05). (2) Improvement in muscle strength and vertical jumping performance was significantly greater in the HL-BFR-RT group than that in the LL-BFR-RT group (P <.05). (3) The HL-BFR-RT group had greater but not significant improvement in muscle strength and vertical jumping performance than that in the HL-RT group.ConclusionsAlthough increases in muscle strength were observed between training groups, HL-BFR-RT increased not only muscle strength but vertical jumping performance to a greater extent compared to LL-BFR-RT and HL-RT.

The evaluation of muscle strength and architecture in type 1 diabetes mellitus: a cross-sectional study

BackgroundThe aim of this study is to compare muscle strength and architecture between type 1 diabetes patients and healthy volunteers and to assess whether there is an ultrasonographic structural change in this population.MethodsThirty-two patients with T1D (23 female, 9 male) with an age average of 31.3 ± 8.7 years, matched in terms of age, gender, height, weight and physical activity were included in the study. In the T1D and control group, ultrasonographic measurements of quadriceps femoris muscle (RF, VI, VM, VL) and pennate angle (VI, VM, VL) were performed. Muscle strength values were measured using isokinetic dynamometer system at angular velocities of 60º/s and 180º/s in both groups.ResultsInitially, both groups were similar in demographic and clinical characteristics (p > 0.05). In the T1D group, there was a statistically significant difference in flexion/extension peak torque measurements at an angular velocity of 60º/s compared to the control group (p < 0.05). In support of these isokinetic measurements, RF, VI, VM, VL muscle thicknesses and VI, VM pennate angle measurements in T1Ds were significantly lower (p < 0.05). When the T1D group was subgrouped according to HbA1C and diabetes duration, there was no significant difference in ultrasonographic and isokinetic measurements between the two groups (p > 0.05). When the T1D group was subgrouped, in the group that used insulin pump RF, VI, VM muscle thickness measurements were significantly higher (p < 0.05) than the group using subcutaneous insulin.ConclusionsThis study supports that muscle strength and architecture are adversely affected in the T1D patient group, insulin deficiency is a risk factor for sarcopenia and this can be shown through ultrasonography. It can also be said that insulin pump use has more positive effects in terms of diabetic myopathy than subcutaneous insulin, and diabetic myopathy develops independently of other diabetic complications. As a result, the muscle architecture of T1D people is adversely affected by insulin deprivation, so regular physical activity should be an integral part of diabetes treatment.

Strength Abilities and Serve Reception Efficiency of Youth Female Volleyball Players

Success in volleyball largely depends on motor abilities, particularly on maximum strength, power, jumping, and speed performance. However, a small number of studies assess the relationship between motor abilities and the effectiveness of volleyball technical skills. Therefore, the aim of the study was to assess the impact of the strength of the upper and lower limbs on the efficiency of serve reception during a 2 vs. 2 game, as well as to evaluate the results of motor measurements in the context of determining the usefulness of current testing procedures. The study involved a carefully chosen group of 12 girls aged 12–13 years (body height: 176.5 ± 4.2 cm, body mass: 58.6 ± 5.1 kg, and training experience: 43 ± 15 months) selected for the Lower Silesian Regional Volleyball Team. The following tests were conducted: handgrip strength with a hand dynamometer, bent-arm hang, 2 kg medicine ball throw, shoulder joint internal rotators (IR) peak torque, standing long jump, spike jump, and countermovement jump. The measurements of the shoulder joint IR peak torque were performed under isometric (at 10°, 35°, and 65° rotation angles) and isokinetic (at 60°/s, 180°/s, and 300°/s) conditions. The efficiency of serve reception was evaluated during a 2 vs. 2 games by using Data Volley statistical software. The strongest positive relationships were observed between the serve reception efficiency and the peak torque and power of the shoulder joint IR, the medicine ball throw distance, and handgrip strength. Jumping variables showed no associations with efficient of serve reception. Consequently, we suggest adding protocols to volleyball training that include strength exercises aimed at developing the IR muscle group. The isokinetic upper limb test should be introduced as a valid tool in selection process. Coaches who do not have access to modern research equipment should use the medicine ball throw test to evaluate strength abilities as an alternative assessment of the serve reception efficiency.

Comparison of the Therapeutic Effects Between Isokinetic and Isotonic Strength Training in Patients After Total Knee Replacement: A Prospective, Randomized Controlled Trial.

Background:Rebuilding the strength of the quadriceps as soon as possible after total knee replacement (TKR) is important so as to restore gait stability. To date, there are no standard postoperative strength training programs during the early recovery stage after TKR.Purpose:To compare the therapeutic effects between isokinetic and isotonic strengthening in patients after TKR.Study Design:Randomized controlled trial; Level of evidence, 1.Methods:From April 2018 to August 2020, 37 patients met the inclusion criteria and were randomly assigned to perform either 4-week isokinetic or isotonic strength training programs. Other components of the rehabilitation program were kept the same between the 2 groups. All cases were evaluated by the Timed Up and Go (TUG) test, peak torque of knee extension and flexion (60 and 120 deg/s), 36-item Short Form Health Survey (SF-36), and Western Ontario and McMaster Universities Arthritis Index (WOMAC).Results:After undergoing a 4-week strength training regimen, significant improvements in the TUG test were noted in both groups; however, the time improvement in the isotonic group did not reach the minimal detectable change. All peak torque measurements improved in the isokinetic group but not in the isotonic group for knee flexion at 60 deg/s. The pain subdomain, physical domain, mental domain, total SF-36 score, and WOMAC index all improved significantly in both groups after training. Both training groups improved significantly in peak torque of knee strength, TUG test, and functional scores, but the differences between isokinetic and isotonic training were not statistically significant.Conclusion:The study findings showed that a 4-week strengthening exercise program in the early postoperative stage, involving either isokinetic or isotonic training, resulted in significant improvements in patients undergoing TKR.Registration:NCT02938416 (ClinicalTrials.gov identifier).

A Custom-Made Electronic Dynamometer for Evaluation of Peak Ankle Torque after COVID-19.

The negative effects of SARS-CoV-2 infection on the musculoskeletal system include symptoms of fatigue and sarcopenia. The aim of this study is to assess the impact of COVID-19 on foot muscle strength and evaluate the reproducibility of peak ankle torque measurements in time by using a custom-made electronic dynamometer. In this observational cohort study, we compare two groups of four participants, one exposed to COVID-19 throughout measurements and one unexposed. Peak ankle torque was measured using a portable custom-made electronic dynamometer. Ankle plantar flexor and dorsiflexor muscle strength was captured for both feet at different ankle angles prior and post COVID-19. Average peak torque demonstrated no significant statistical differences between initial and final moment for both groups (p = 0.945). An increase of 4.8%, p = 0.746 was obtained in the group with COVID-19 and a decrease of 1.3%, p = 0.953 was obtained in the group without COVID-19. Multivariate analysis demonstrated no significant differences between the two groups (p = 0.797). There was a very good test–retest reproducibility between the measurements in initial and final moments (ICC = 0.78, p < 0.001). In conclusion, peak torque variability is similar in both COVID-19 and non-COVID-19 groups and the custom-made electronic dynamometer is a reproducible method for repetitive ankle peak torque measurements.

Far-infrared-emitting fabric improves neuromuscular performance of knee extensor.

The aim of this study was to verify if exposure to the far-IR emitted by fabric (FIR) is able to improve the neuromuscular performance of the knee extensors of resistance-trained males regardless of changes of the temperature. It is a crossover, randomized, double-blind, and placebo-controlled trial. Fourteen resistance-trained males (age: 24.3 ± 4 years; body mass: 82.8 ± 11.3 kg; height: 176.3 ± 4.2 cm) were randomly assigned to one of initial conditions: FIR (n = 7) or placebo (n = 7). After 4 days, the participants were submitted to neuromuscular tests in an isokinetic dynamometer (maximal isometric voluntary contraction (MVC) and fatigue test). After a week of washout, participants performed the other condition. We measured peak torque (Nm), total work (J), fatigue index (%), root mean square (mV), median frequency (Hz), and temperature (°C) of thigh. The FIR was worn for 82 ± 19 h before the experimental session, totaling 317 ± 74 kJ of energy irradiation. There was a significant increase (p < 0.05) for pre-MVC (318.5 ± 68.7 Nm) and post-MVC (284.1 ± 58.2 Nm), and a trend (p = 0.055) for significant increase for total work (4,122.2 ± 699.8 J) on FIR condition regardless of none change on temperature and electromyographic (EMG) signals. FIR improved the neuromuscular performance of knee extensors in resistance-trained males regardless of changes on temperature and EMG. The present results suggest that the FIR could optimize the neuromuscular performance with 82 ± 19 h of wear.

Knee and hip dynamic muscle strength in individuals with femoroacetabular impingement syndrome scheduled for hip arthroscopy: A case-control study

BackgroundThe primary aim of this study was to compare knee and hip dynamic muscle strength of individuals with femoroacetabular impingement (FAI) syndrome scheduled for hip arthroscopy with healthy controls. Our secondary aim was to compare hip and knee muscle strength between male and female patients with FAI syndrome.MethodsOne hundred and thirty-four individuals with femoroacetabular impingement syndrome scheduled for hip arthroscopy and 134 healthy controls matched for sex and age (within 5 years range) underwent an isokinetic assessment of knee extension and flexion and hip abduction, adduction, external rotation and internal rotation dynamic muscle strength. Two MANOVAs were conducted to compare isokinetic peak torque and total work between groups and sexes.FindingsIndividuals with femoroacetabular impingement syndrome demonstrated lower values of all variables representing knee and hip isokinetic peak torque and total work measures when compared to healthy controls, with differences ranging from 0.09 Nm/kg (95%CI: 0.06–0.12 Nm/kg) to 0.64 Nm/kg (95%CI: 0.49–0.79 Nm/kg). Female participants from both FAI syndrome and control group showed less knee and hip muscle strength compared to male participants. There was no significant interaction between group and sex regarding knee or hip isokinetic peak torque and total work (p > 0.05).InterpretationIndividuals with femoroacetabular impingement syndrome scheduled for hip arthroscopy present impairments in knee or hip dynamic muscle strength when compared to controls. Female participants present less knee and hip muscular strength compared to male participants, these between-sex differences are similar for both FAI syndrome and control group participants.