Relationship between natural muscle oscillation frequency and lower limb muscle performance during instrumented sit-to-stand and stand-to-sit movements on a novel device in sedentary subjects

BACKGROUND

Despite the significance of muscle oscillation frequency, previous research has not established a correlation with muscle performance due to the challenges of applying resistance without altering natural motion during functional tests.

RESEARCH QUESTION

What is the correlation between muscle oscillation frequency and lower limb muscle strength, power, and work during an instrumented sit-to-stand and stand-to- sit (iSTS-TS) task among sedentary subjects?

METHODS

In a cross-sectional study, the oscillation frequency of the gastrocnemius medialis (GM), biceps femoralis (BF), and vastus medialis (VM) muscles in both the dominant (D) and non-dominant (ND) legs was assessed with a handheld myotonometer in 34 sedentary individuals before performing the iSTS-TS task.

RESULTS

In the isokinetic mode, no significant correlations were found. In the isotonic mode, the BF muscle oscillation frequency in the D and ND legs exhibited significant positive correlations with peak force, peak power, and work during sitting down, as well as peak power and work during standing up. Positive correlations were observed in both legs between the GM oscillation frequency and sitting down peak force and work. Additionally, significant positive correlation was found with standing up work in the D leg. Muscle oscillation frequency of the VM exhibited a positive correlation with sitting down peak force in the ND leg.

SIGNIFICANCE

Due to a greater number of correlations found, it is advisable to use the isotonic mode when assessing muscle oscillation frequency in relation to muscle performance during functional iSTS-TS tasks in sedentary subjects.

Reliability of a handball specific strength test battery and the association with sprint and throwing performance in young handball players

BACKGROUND

A greater motivation for coaches to be more involved in assessment could be the development of specific strength tests closer to specific handball tasks. Therefore, the aims were to determine the reliability of a handball specific strength test battery in young handball players using a functional electromechanical dynamometer (FEMD) and to evaluate the association between the strength test battery and performance measurements.

METHODS

Thirty-two young handball players (25% males and 75% females) performed a repeated-measurement design over four weeks. The players conducted one session per week, with each measurement consisting of two isometric tests to obtain isometric peak force, and four incremental tests. Moreover, performance handball tests (sprint and throwing velocity [TV]) were recorded.

RESULTS

The reliability of the whole handball specific strength tests was very high for the peak and mean strength (ICC=0.70-0.85; CV=8.49-13.99; SEM=0.44-0.67 kg). The step forward had a moderate association with 5 to 10 meters' time. The highest correlation between TVmean was found with the peak strength of standing lift and between TVpeak with peak strength of unilateral throw. The sprint total time could be explained by Body Mass Index and peak strength of the standing lift in the 40% and the TVpeak could be explained by arm span and mean strength of the standing lift in the 68%.

CONCLUSIONS

The high reliability for all exercises and the significant correlation with handball performance (sprint time and TV) allow us to include these tests in handball team evaluation and training.

Reliability of two devices for shoulder strength assessment: Wii Fit Balance Board and hand-held dynamometer

Background

The aim of this study was to compare the reliability and agreement between two devices - Wii Fit Balance Board (WBB) versus Hand-Held Dynamometer (HHD) to measure isometric strength during the athletic shoulder (ASH) test in healthy amateur rugby players.

Methods

Fifteen males (23.73 ± 2.8 years) completed two testing sessions. Maximal isometric contractions using the dominant arm (D) and non-dominant arm (ND) against a WBB and HHD were assessed at three angles of abduction (180°, 'I'; 135°, 'Y' and 90°, 'T'), in a prone lying position.

Results

The results indicate a very large correlation between the HHD and the WBB. WBB provides acceptable reliability at I-Test D (CV = 9.97%, ICC = 0.88) and HHD in the I-Test D (CV = 8.90%, ICC = 0.94), I-Test ND (CV = 8.60%, ICC = 0.95) in peak strength values. The HHD is most reliable in D ASH I-Y-T (CV = 10.94%) and WBB (CV = 11.05%). In the ND ASH I-Y-T test, the HHD is the most reliable (CV = 12.5%) compared to the WBB (CV = 14.43%).

Conclusions

These results suggest that WBB is a reliable device to assess strength in the ASH test with a very large correlation with the HHD. WBB and HHD are two affordable devices to assess isometric shoulder strength.

Does the Position of the Ankle Matter During the Single Gluteal Bridge in Futsal Players? An Electromyographic Analysis

CONTEXT

The aim of this study was to analyze the muscle activity of the hamstring muscles and the lateral gastrocnemius during different variants of the single-leg bridge (SLB) in futsal players.

DESIGN

Cross-sectional study.

METHODS

Twenty-two futsal players (age = 24.8 [3.9] y) volunteered to participate in this study. The participants performed 3 variations of the SLB with the knee flexed at 45°. The first position was performed with the ankle in plantar position with flat support, the second with the ankle in dorsiflexion (DF) with heel support, and the third with the ankle in DF and external rotation (ER) with heel support. The Wilcoxon rank-sum test assessed the difference between variables for samples with the rank-biserial correlation effect size. Spearman correlation coefficients were used to examine the associations of the percentage maximal voluntary isometric contraction for each muscle with peak force and rate of force development with 3 different variances of the SLB.

RESULTS

The variation of ankle DF and ER with heel support generated higher muscle activity in BF in concentric (P < .01, effect size [ES] = -0.613); isometric (P < .042, ES = -0.494); and eccentric (P < .005, ES = -0.668) contraction than ankle DF with heel support. In contrast, the variation of ankle DF and ER with heel support generated fewer muscle activity in lateral gastrocnemius in concentric (P < .001, ES = 0.779); isometric (P < .003, ES = 0.708); and eccentric (P < .014, ES = 0.589) contraction than ankle DF with heel support.

CONCLUSIONS

The position of DF and ER was the best position in SLB to train the BF. It could be convenient to start rehabilitation of the BF with flat foot postition or ankle in DF with heel support and progress with the position of the ankle in DF and ER with heel support.

Test-Retest Reliability of 3 Specific Strength Tests in Professional Handball Players

CONTEXT

Current devices to assess strength performance in handball may not be sufficiently sports-specific and reliable methods. Functional electromechanical dynamometry is a new technology that allows the development of accurate strength tests in athletes.

PURPOSE

To determine the absolute and relative reliability and to compare the reliability of the right and left side, and mean and peak force of 3 specific strength tests in handball players with a functional electromechanical dynamometer: unilateral pullover, standing lift, and step forward.

METHODS

Fourteen male handball players of the first Spanish division (28.79 [4.81] y; 10.38 [4.63] y of professional experience) performed a repeated-measurement design. Three testing sessions were performed (one per week). The first measurement consisted of 4 isometric tests (right and left unilateral pullover, and right and left standing lift) to obtain isometric peak force, and in the second and third sessions, 6 incremental tests until failure (right and left unilateral pullover, and right and left standing lift, right and left step forward) were performed.

RESULTS

The tests provided high reliability or acceptable reliability for mean and peak strength of unilateral pullover, standing lift and step forward (intraclass correlation coefficient = .83-.97; coefficient of variation = 3.90-11.57). Effect side was negligible in any of the parameters, except for a small effect side in the left peak force for unilateral pullover and a small effect side on the left side for a step forward. Significant differences in reliability (coefficient of variation ratio > 1.15) were found between the right and left sides and peak and mean force in all exercises except peak force in unilateral pullover and step forward.

CONCLUSION

These results confirm that the tests could be applied to assess physical performance in handball at the same time as regular gym training. Moreover, this is an excellent opportunity to individualize the player's weekly load.

Impact of Starting Knee Flexion Angle on Muscle Activity and Performance during Plyometrics without Jumping

Most of the existing research has focused on jump plyometrics, where landing reaction forces must be dissipated among lower limb articulations. In contrast, the investigation of resisted plyometrics without jumping, devoid of such landing forces, remains relatively limited. This study aimed to (i) investigate the impact of resisted plyometrics without jumping at two knee flexion angles (60 and 90 degrees) on vastus muscle activity relative to limb dominance and (ii) assess strength, power, and work during the concentric-eccentric phases of these exercises. Thirty-one healthy participants underwent quantification of lower limb muscle amplitude, strength, power, and work during resisted plyometrics without jumping from both 60° and 90° knee flexion positions. After anthropometric evaluations, participants used a dynamometer with a load equal to 80% of body weight while wireless surface electromyography electrodes recorded data. Statistical analyses utilized paired t-tests or nonparametric equivalents and set significance at p ≤ 0.05. Results showed significantly higher muscle activity in the vastus medialis (VM) (dominant: 47.4%, p = 0.0008, rs = 0.90; nondominant: 54.8%, p = 0.047, rs = 0.88) and vastus lateralis (VL) (dominant: 46.9%, p = 0.0004, rs = 0.86; nondominant: 48.1%, p = 0.021, rs = 0.67) muscles when exercises started at 90° knee flexion, regardless of limb dominance. Substantial intermuscle differences occurred at both 60° (50.4%, p = 0.003, rs = 0.56) and 90° (54.8%, p = 0.005, rs = 0.62) knee flexion, favoring VM in the nondominant leg. Concentric and eccentric strength, power, and work metrics significantly increased when initiating exercises from a 90° position. In conclusion, commencing resisted plyometrics without jumping at a 90° knee flexion position increases VM and VL muscle activity, regardless of limb dominance. Furthermore, it enhances strength, power, and work, emphasizing the importance of knee flexion position customization for optimizing muscle engagement and functional performance.

Muscle Quality Index is inversely associated with psychosocial variables among Chilean adolescents

A good muscle quality index (MQI) may have an inverse relationship with psychosocial variables of depression, anxiety, and stress in adolescents. Unfortunately, little scientific evidence has related MQI to psychosocial variables in this population. Therefore, this research aimed to determine the relationship between the MQI and psychosocial variables of depression, anxiety, and stress in Chilean adolescents. In this quantitative correlational design study, sixty adolescents participated voluntarily (mean ± standard deviation [SD]: age 15.11 ± 1.78 years). Anthropometric parameters, prehensile strength, MQI, and psychosocial variables were evaluated. The results showed that adolescents with high levels of MQI presented lower levels of depression (7.50 ± 6.06 vs. 10.97 ± 5.94), anxiety (5.64 ± 4.81 vs. 9.66 ± 5.12), and stress (6.79 ± 5.09 vs. 10 ± 5.58), in addition to reported lower abdominal obesity (WtHR, 0.47 ± 0.07 vs. 0.52 ± 0.07) than those with low levels of MQI. The group with high levels of MQI reported a higher prevalence of nonanxiety (81.3%, p = 0.031) and a lower prevalence of abdominal obesity (55.8%, p = 0.023). Likewise, a significant inverse association was evidenced between MQI and depression (β; -6.18, 95% CI; -10.11: -2.25, p = 0.003), anxiety (β; -6.61, 95% CI; -9.83: -3.39, p < 0.001) and stress (β; -4.90, 95% CI; -8.49: -1.32 p = 0.008). In conclusion, the results suggest that high levels of MQI are associated with a higher prevalence of nonanxiety in adolescents and a significant inverse association between MQI and levels of depression, anxiety, and stress.

Core training and performance: a systematic review with meta-analysis

The purposes were to synthesize as much scientific evidence as possible to determine the effect of core training on balance, throwing/hitting velocity or distance, and jumping in healthy subjects, identify the possible differences between isolated and combined core training on performance and study training and sample variables related to performance. PRISMA guidelines were followed, and a systematic search was performed in the Scopus, Web of Science, Sports Discuss, and PubMed databases with no date restrictions until November 2022. The studies were considered for this meta-analysis following PICO; a) randomized control trials and randomized allocation studies with healthy subjects and > 12 years old b)isolated or combined core training programs with a minimum of 4 weeks in length; c) athletic performance outcomes for balance, throw/hit, and jump variables should be measured; d) sufficient data to calculate effect sizes. The Cochrane Collaboration Risk of Bias Tool and the Grading of Recommendations Assessment, Development, and Evaluation approach were used for assessing methodological quality. A total of 3223 studies were identified, 22 studies were included in the systematic review and 21 for the meta-analysis. We observed that core training improved balance outcomes (ES = 1.17; p < 0.0001), throwing/hitting velocity (ES = 0.30; p = 0.14), throwing/hitting distance (ES = 3.42; p = 0.03), vertical jumping (ES = 0.69; p = 0.0003), and horizontal jump (ES = 0.84; p = 0.01). Our findings indicate that core training improved different variables of performance such as balance, throw/hit, and vertical and horizontal jump.

Effects of Exergames and Conventional Physical Therapy on Functional Physical Performance in Older Adults: A Randomized Controlled Trial

Objective: To evaluate the effects of exergames added to a conventional physical therapy (CPT) program on functional fitness and dynamometric muscle performance for the sit-to-stand (STS) maneuver in older adults and to compare their results concerning a CPT-only intervention. Materials and Methods: Fifty independent older adults were randomly assigned to CPT and exergames (CPT+ExG group; n = 25; age = 71.8 ± 6.8 years) or CPT alone (CPT group; n = 25; age = 71.3 ± 7.4 years). CPT was performed twice a week (60 min/session) for 8 weeks. The CPT+ExG group added exergames for 30 minutes in each session. The Senior Fitness Test was applied, considering the 30-second chair stand test as the primary outcome. Additionally, dynamometric muscle performance during the STS maneuver was assessed. Results: The CPT+ExG group improved the 30-second chair stand (lower body strength), back scratch (upper body flexibility), and 8-foot up-and-go (agility/dynamic balance) tests (all P < 0.05). Both groups improved the kinetic dynamometric variables peak force, peak power, and total work (all P < 0.05). Also, both groups improved the 30-second arm curl test (upper body strength) (P < 0.05), although the increase was higher in the CPT+ExG group compared with the CPT group (time × group; P < 0.05). Conclusion: Adding exergames to a CPT program only significantly increases upper limb strength compared with CPT alone. The findings of this study have implications for the design of future exergame interventions focused on improving STS maneuver performance in older adults.

Effects of Power Training on Functional Capacity Related to Fall Risk in Older Adults: A Systematic Review and Meta-analysis

OBJECTIVE

Functional capacity is 1 of the main risk factors for falls among older adults. The aim of this systematic review and meta-analysis was to determine the effect of power training on functional capacity test (FCT) related to fall risk in older adults.

DATA SOURCES

Systematic searches were conducted in 4 databases, including PubMed, Web of Science, Scopus, and SPORTDiscus, from inception to November 2021.

STUDY SELECTION

Randomized controlled trials (RCTs) assessing the effect of power training on functional capacity compared with another type of training program or control group in older adults with the ability to exercise independently.

DATA EXTRACTION

Two independent researchers evaluated eligibility and used the PEDro scale to assess risk of bias. The information extracted was related to article identification (authors, country and year of publication), participant characteristics (sample, sex, and age), strength training protocols (exercises/intensity/weeks), and the outcome of the FCT used related to fall risk. The Cochran Q statistic and I2 statistics was used to assess heterogeneity. Random-effects model were conducted to pool the effect sizes expressed as mean differences (MD).

DATA SYNTHESIS

Twelve studies (478 subjects) were selected for systematic review. A meta-analysis comprised 6 studies (217 subjects) where the outcome measure was the 30-second Sit to Stand (30s-STS) test, and another comprised 4 studies (142 subjects) where the outcome measure was the timed Up and Go (TUG) test. There was an improvement in performance in favor of the experimental group in both the TUG subgroup (MD -0.31 s; 95% CI -0.63, 0.00 s; P=.05), and the 30s-STS subgroup (MD 1.71 reps; 95% CI -0.26, 3.67 reps; P=.09).

CONCLUSIONS

In conclusion, power training increases functional capacity related to fall risk further than other types of exercise in older adults.

Strength Assessment of Trunk Rotator Muscles: A Multicenter Reliability Study

BACKGROUND

Trunk rotator strength plays an important role in sports performance and health. A reliable method to assess these muscles with functional electromechanical dynamometer has not been described. Therefore, the objectives of this paper were (I) to explore the reliability of different strength variables collected in isokinetic and isometric conditions during two trunk rotator exercises, and (II) to determine the relationship of isometric and dynamic strength variables collected in the same exercise.

METHODS

A repeated measures design was performed to evaluate the reliability of the horizontal cable woodchop (HCW) and low cable woodchop (LCW) exercises. Reliability was assessed using t-tests of paired samples for the effect size, the standard error of measurement, the coefficient of variation (CV) and the intraclass correlation coefficient (ICC). The Pearson's (r) correlation coefficient was used to explore the association between isometric and isokinetic tests.

RESULTS

HCW exercise is more reliable than LCW exercise in assessing trunk rotator muscles. The strength manifestation that should be used is the average strength, and the most reliable evaluation was the HCW at 0.40 m·s-1 concentric (ICC = 0.89; CV = 10.21%) and eccentric (ICC = 0.85; CV = 9.33%) contraction and the dynamic condition that most correlated with the isometric was LWC at 0.50 m·s-1 (r = 0.83; p < 0.01).

CONCLUSION

HCW is a reliable exercise to measure trunk rotator muscles.

Males Have a Higher Energy Expenditure than Females during Squat Training

The main objective of this study was to determine the differences in energy expenditure (EE) according to sex during and after two different squat training protocols in a group of healthy young adults. Twenty-nine Sports Sciences students volunteered to participate in this study. They attended the laboratory on four different days and completed four sessions: two sessions with 3 sets of 12 repetitions at 75% of their one-repetition maximum (RM) and two sessions with 3 sets of 30 repetitions at 50% of their 1RM. Energy expenditure was evaluated using an indirect calorimeter. Males consistently demonstrated higher EE in all sessions and intensities. The linear regression model identified a significant association between sex, BMI, and total EE across all sessions and intensities. In conclusion, males exhibited higher EE in both protocols (50% and 75% of 1RM) throughout all sessions. Furthermore, sex and BMI were found to influence EE in healthy young adults. Therefore, coaches should consider sex when assessing EE, as the metabolic response differs between males and females.

Effect of sit-to-stand-based training on muscle quality in sedentary adults: a randomized controlled trial

The aim of this study was to compare the effects of sit-to-stand (STS) training programs with 5 vs. 10 repetitions on muscle architecture and muscle function in sedentary adults. Sixty participants were randomly assigned into three groups: five-repetition STS (5STS), 10-repetition STS (10STS), or a control group (CG). Participants performed three sets of five or 10 repetitions of the STS exercise three times per week for 8 weeks. Before and after 8 weeks, all groups performed ultrasound measures to evaluate muscle thickness (MT), pennation angle (PA), and fascicle length (FL), and the five-repetition STS test to estimate the relative STS power and muscle quality index (MQI). After 8 weeks, both experimental groups improved MQI (40-45%), relative STS power (29-38%), and MT (8-9%) (all p < 0.001; no differences between the 5STS vs. 10STS groups). These improvements in both groups resulted in differences regarding the CG, which did not present any change. In addition, only the 5STS group improved PA (15%; p = 0.008) without differences to the 10STS and CG.This suggests that STS training is time-effective and low-cost for improving muscle function and generating adaptations in muscle architecture.

Muscle Quality Index in Morbidly Obesity Patients Related to Metabolic Syndrome Markers and Cardiorespiratory Fitness

BACKGROUND

Muscle quality index (MQI) is an emerging health indicator obtained by dividing handgrip strength by body mass index (BMI) that needs to be studied in morbidly obese patients (defined by BMI ≥ 35 kg/m²).

OBJECTIVE

To determine the association between MQI, metabolic syndrome (MetS) markers, and cardiorespiratory fitness (CRF), and as a second objective to determine the potential mediation role of MQI in the relationship between abdominal obesity and systolic blood pressure (SBP) in this sample.

METHODS

This cross-sectional study included 86 severely/morbidly obese patients (age = 41.1 ± 11.9 y, nine men). MQI, metabolic syndrome markers, CRF, and anthropometric parameters were measured. Two groups were developed according to MQI; High-MQI (n = 41) and Low-MQI (n = 45).

RESULTS

The Low-MQI group reported higher abdominal obesity (High-MQI: 0.7 ± 0.1 vs. Low-MQI: 0.8 ± 0.1 WC/height; p = 0.011), SBP (High-MQI: 133.0 ± 17.5 vs. Low-MQI: 140.1 ± 15.1 mmHg; p = 0.048), and lower CRF (High-MQI; 26.3 ± 5.9 vs. Low-MQI; 22.4 ± 6.1 mL/kg/min, p = 0.003) than the High-MQI group. Waist-to-height ratio (β: -0.07, p = 0.011), SBP (β: -18.47, p = 0.001), and CRF (β: 5.21, p = 0.011) were linked to MQI. In a mediation model, the indirect effect confirms that MQI is a partial mediator of the association between abdominal obesity with SBP.

CONCLUSIONS

MQI in morbidly obesity patients reported an inverse association with MetS markers and a positive association with CRF (VO2_max). It mediates the relationship between abdominal obesity and SBP.

Test-Retest Reliability of the Functional Electromechanical Dynamometer for Squat Exercise

BACKGROUND

the main objective of this study was to evaluate the test-retest reliability of two different functional electromechanical dynamometry (FEMD)-controlled squat training protocols.

METHODS

twenty-eight healthy young adults volunteered to participate in this study. They attended the laboratory on four different days and performed four sessions: two of three sets of 12 repetitions at 75% 1RM and two of three sets of 30 repetitions at 50% 1RM. The range of movement (ROM), mean dynamic strength (MDS), peak dynamic strength (PDS), mean velocity (MV), peak velocity (PV), mean potency (MP), peak potency (PP), work (W), and impulse (I) were recorded. To evaluate the reliability of FEMD, the intraclass correlation coefficient (ICC), standard error of measurement (SEM), and coefficient of variation (CV) were obtained.

RESULTS

reliability was very high for ROM (CV: 3.72%, ICC: 0.95), MDS (CV: 1.09%, ICC: 1.00), PDS (CV: 1.97%, ICC: 1.00), and W (CV: 4.69%, ICC: 1.00) conditions at 50% 1RM and for ROM (CV: 3.90%, ICC: 0.95), MDS (CV: 0.52, ICC: 1.00), PDS (CV: 1.49%, ICC: 0.98), and W (CV: 4.14%, ICC: 1.00) conditions at 75% 1RM and high for the rest of variables at 50 and 75% 1RM.

CONCLUSIONS

this study demonstrates that FEMD is a reliable instrument to measure ROM, MDS, PDS, MV, PV, PV, MP, MP, W, and I during both squat protocols (50 and 75% 1RM) in healthy young adults.

Dynamometric Strength Profile of Hip Muscles in Youth Soccer Players

BACKGROUND

Soccer is the most widely practiced sport in the world, demanding high-speed activities such as jumps, sprints and changes of direction. Therefore, having optimal levels of muscle strength improves performance and reduces the injury rate.

OBJECTIVES

The objectives of our study were (i) to determine the dynamometric profile of hip muscle strength in young soccer players by position, evaluated at different isokinetic speeds, (ii) to describe the conventional and functional unilateral muscle strength ratios, (iii) to analyze the bilateral balance.

METHODS

Thirty-seven male soccer players (age 17.02 ± 0.92 years) participated in the study. Strength assessment was performed with a functional electromechanical dynamometer, and concentric and eccentric strength of abductors, adductors, extensors and hip flexors were measured bilaterally at 0.5 m/s and 1 m/s.

RESULTS

For eccentric right hip abduction at 0.5 m/s, defenders are significantly stronger than midfielders (p = 0.013) and stronger than forwards (p = 0.140). For eccentric right hip adduction at 0.5 m/s, defenders are significantly stronger than midfielders (p = 0.005) and stronger than forwards (p = 0.253), as for eccentric right hip adduction at 1 m/s, defenders are significantly stronger than midfielders (p = 0.014) and stronger than forwards (p = 0.084). There is a significant effect for the conventional strength ratio of left abduction/adduction at 1 m/s. The conventional strength ratio of forwards is significantly higher than that of defenders (p = 0.045) and higher than that of midfielders (p = 0.152).

CONCLUSIONS

Concentric and eccentric hip strength values differ according to playing position.

Isokinetic trunk training on pain, disability, and strength in non-specific low back pain patients: A systematic review and meta-analysis

BACKGROUND

Low back pain is one of the leading causes of disability globally, with a high economic and social burden. A decrease or imbalance in trunk strength has been associated with the occurrence of low back pain and its severity. Trunk strength training is helpful in the treatment of Non-specific low back pain (NSLBP) patients. However, we do not know the effects of trunk isokinetic training (IKT) on pain intensity, disability, and trunk strength.

OBJECTIVE

This systematic review aimed to determine the effects of trunk IKT in NSLBP patients on pain intensity, disability, and trunk flexor and extensor isokinetic strength.

METHODS

We searched PubMed, Web of Science, Scopus, CENTRAL, and PEDro, from January 2001 until March 2021 and updated to November 2022. Randomized controlled trials (RCTs) that investigated the effect of IKT in adult participants with NSLBP on pain intensity, disability, or isokinetic trunk strength were included. Mean difference (MD) and 95% confidence intervals (95% CI) were calculated for pain. Bias was assessed using the Cochrane risk of bias (RoB) tool and evidence certainty via Grading of Recommendations Assessment, Development and Evaluation (GRADE).

RESULTS

Among 1750 retrieved articles, eight were included in this review. Meta-analysis comparing IKT (trunk isokinetic training, n= 134) with control groups (conventional exercises, n= 133) revealed that IKT decreases pain intensity (MD -1.50 (95% CI: -2.60; -0.39)) immediately post-intervention, and one month (MD -1.97 (95% CI: -2.92; -1.03)) and at six months follow-up (MD -2.48 (95% CI: -2.77; -2.19)), although with a very low to low quality according to the GRADE rating. Besides, IKT decreases disability and increases isokinetic trunk strength, but with scant evidence.

CONCLUSIONS

Trunk IKT could be a novel clinical tool for pain management in patients with NSLBP, although evidence is scarce. In addition, few RCTs exist for IKT on disability or trunk isokinetic strength in patients with NSLBP. Therefore, further research on this topic is needed.

Exploration of the Shoulder Internal Rotation's Influence on Throwing Velocity in Handball Players: A Pilot Study

The main objective of this study was to test the relationship between shoulder internal rotation strength and standing throwing velocity. A repeated measures cross-sectional study was conducted with 20 professional handball players (mean ± SD; age: 19.28 ± 2.55 years, weight: 81.52 ± 9.66 kg, height: 185 ± 6 cm, BMI: 23.74 ± 1.69). The participants were instructed to perform eight standing throws from the 7 m line of the handball court at maximum velocity to calculate the mean and maximum throwing velocity. An incremental test was performed to calculate the repetition maximum (1-RM) of internal rotation shoulder strength. A Pearson's correlation analysis with a 95% confidence interval (95% CI) was performed to determine whether correlations existed between dominant arm internal rotation strength characteristics and maximum and mean ball-throwing velocity. There is no correlation between the internal rotation strength of the throwing shoulder and the velocity of the ball in the standing handball throw.

Self-perceived cognitive function and neuropsychological performance in women with fibromyalgia

BACKGROUND

Cognitive dysfunction is a common complain in patients with fibromyalgia (FM).

AIM

To assess the perceived cognitive function and cognitive performance in women with FM.

MATERIAL AND METHODS

Cross-sectional study including 100 women with FM (FMG) and 100 healthy controls (CG). Self-perceived cognitive functioning was evaluated using the Functional Assessment of Cancer Therapy Cognition scale (FACT-Cogv3). The neuropsychological performance was assessed with the Trail Making Test (TMT-A, TMT-B), Digit Span test (DS), Barcelona test (DS-F/B) and the Frontal Assessment Battery (FAB-E), Spanish version test.

RESULTS

The mean scores of all cognitive self-perception factors and all neuropsychological tests were lower in the FMG (p < 0.001). Over 90% of the FMG took longer than the population mean (P50) to complete the TMT-A and TMT-B tests, while in the CG, 1/3 took longer than the P50 in both tests. The minimum expected scores for the DS-F and DS-B tests were not achieved by 40 and 9% of FMG participants, respectively. According to FAB-E, 54% and 24% of FMG were categorized as fronto-subcortical deficit and fronto-subcortical dementia, respectively.

CONCLUSIONS

Women with FM have a higher perception of cognitive dysfunction and lower cognitive performance in objective tests than healthy women. More research is needed to explore the clinical, psychosocial, and sociodemographic characteristics that predispose to cognitive deficits in this group of patients.

Muscle Quality and Functional and Conventional Ratios of Trunk Strength in Young Healthy Subjects: A Pilot Study

BACKGROUND

The trunk strength conventional ratio (CR) has been evaluated. However, the functional ratio and the ratio of strength to body weight (BW) or muscle mass (MM) have been poorly explored. Relative strength is a measure of muscle quality.

OBJECTIVES

To analyze the trunk strength ratio normalized by BW and MM and compare the trunk's conventional and functional ratios collected in isokinetic and isometric conditions.

METHODS

Twenty-seven healthy males (21.48 ± 2.08 years, 70.22 ± 7.65 kg) were evaluated for trunk isometric and isokinetic strength using a functional electromechanical dynamometer.

RESULTS

The extensor's strength was greater than the flexors, with a CR of 0.41 ± 0.10 to 0.44 ± 0.10. Muscle quality was higher in eccentric contraction and high velocity for flexors and extensors. The functional flexor ratio (FFR) ranged between 0.41 ± 0.09 and 0.92 ± 0.27. The functional extensor ratio (FER) ranged between 2.53 ± 0.65 and 4.92 ± 1.26. The FFR and FER showed significant differences between velocities when considering the peak strength (p = 0.001) and mean strength (p = 0.001).

CONCLUSIONS

Trunk extensors were stronger than the flexors; thus, the CR was less than one. Muscle quality was higher at a high velocity. Unlike CR, FFR and FER behaved differently at distinct velocities. This finding highlights the need to explore the behavior of the functional ratio in different populations.

Reliability of trunk strength measurements with an isokinetic dynamometer in non-specific low back pain patients: A systematic review

BACKGROUND

Imbalance or decreased trunk strength has been associated with non-specific low back pain (NSLBP).

OBJECTIVE

This systematic review aimed (I) to evaluate the quality of evidence of studies evaluating the reliability of trunk strength assessment with an isokinetic dynamometer in NSLBP patients, (II) to examine the reliability of trunk strength assessment using an isokinetic dynamometer in NSLBP patients and (III) to determine the most reliable protocol for trunk strength assessment in NSLBP patients.

METHOD

PRISMA guidelines were followed. Three databases were used: PubMed, Scopus, and Web of Science with the following keywords: Isokinetic, Dynamometer, Trunk strength testing, Muscle testing, Isokinetic measurement, CORE, Abdominal muscles, Abdominal wall, Torso, Trunk, Spine, Reliability and, Reproducibility. We included only test-retest studies, focused on the reliability of isometric and isokinetic strength assessed with an isokinetic dynamometer in NSLBP adults' patients, published in English and from inception to March 30, 2021. The methodological quality was evaluated with the CAT scale and QAREL checklist.

RESULTS

Five hundred and seventy-seven articles were retrieved, of which five are included in this review. Three articles provide good quality of evidence, the reliability of trunk strength assessment in NSLBP patients is excellent, and the most reliable protocol for isometric assessment is in a seated position (ICC = 0.94-0.98) and for isokinetic strength in standing position, at 60∘/s and 120∘/s (ICC = 0.98).

CONCLUSION

There is good quality evidence regarding the trunk strength assessment's reliability. Reliability is excellent in NSLBP patients; however, a familiarization process should be considered to obtain clinically reliable data. The most reliable protocol is in a seated position for isometric strength and a standing position for isokinetic strength.

Effects of bariatric surgery on cardiorespiratory fitness: A systematic review and meta-analysis

Although bariatric surgery (BS) is recognized as an effective strategy for body weight loss, its impact on cardiorespiratory fitness (CRF) is still unclear. We aimed to examine postoperative changes in CRF (VO_2max/peak ) and its relationship with weight loss among adults undergoing BS. We systematically searched the WoS, PubMed, MEDLINE, and Scopus databases. Observational and intervention studies were selected reporting the presurgery and postsurgery CRF, measured by breath-by-breath VO₂ or its estimation. Eleven articles (312 patients) revealed that BS leads to a reduction in absolute VO_2max/peak in the short term (effect size, ES = -0.539; 95%CI = -0.708, -0.369; p < 0.001), and those patients who suffered a more significant decrease in BMI after BS also had a greater loss of absolute VO_2max/peak . However, VO_2max/peak relative to body weight increased after surgery (ES = 0.658; 95%CI = 0.473, 0.842; p < 0.001). An insufficient number of studies were found investigating medium and long-term changes in CRF after BS. This study provides moderate-quality evidence that the weight loss induced by BS can reduce CRF in the short term, which represents a therapeutic target to optimize BS outcomes. More high-quality studies are needed to evaluate the impact of BS on VO_2max/peak in the short, medium, and long term including normalized values for fat-free mass.

Supine scapular punch: An exercise for early phases of shoulder rehabilitation?

BACKGROUND

Serratus anterior strengthening generally appears in shoulder rehabilitation protocols. This study's aim was to measure electromyographic activity of the serratus anterior, upper trapezius, and infraspinatus muscles during the Supine Scapular Punch exercise in healthy volunteers and those with unilateral shoulder pain.

METHODS

Fifty-four participants were included and grouped as without (n = 34, age = 25.8 years) or with unilateral shoulder pain (n = 20, age = 26.3 years, visual analogue scale = 4.15 cm). Electromyographic activity of the serratus anterior, upper trapezius, and infraspinatus muscles was assessed during Supine Scapular Punch (four phases: P1 = press up concentric, P2 = Supine Scapular Punch concentric, P3 = Supine Scapular Punch eccentric, P4 = press up eccentric) performed under two conditions, with and without additional load.

FINDINGS

Overall muscle activity during P1 and P4 was negligible (< 10% maximal voluntary isometric contractions). During P2 and P3, no statistically significant differences in serratus anterior and upper trapezius muscle activity were found between groups, with moderate to high serratus anterior activity (28.94% to 44.3%) and very low upper trapezius activity (< 6%). Upper trapezius/serratus anterior activity ratios ranged from 0.09 to 0.18. Overall infraspinatus muscle activity was always very low (< 10%).

INTERPRETATION

The Supine Scapular Punch induces moderate to high serratus anterior muscle activity with very low upper trapezius and infraspinatus activation. Based on these results, the Supine Scapular Punch is a safe exercise that can be used in the early phases of shoulder rehabilitation.

The association between modifiable lifestyle behaviour in Latin-American schoolchildren with abdominal obesity and excess weight. A comparison of Chile and Colombia

OBJECTIVE

The purpose was to determine the association of lifestyle (i.e., Mediterranean diet [MD] adherence, physical activity [PA], screen time [ST]) and fitness with abdominal obesity (AO) and excess weight in the Chilean and Colombian schoolchildren.

RESEARCH METHODS & PROCEDURES

This cross-sectional study included 969 schoolchildren, girls (n=441, 5.24±0.80 years old) and boys (n=528, 5.10±0.78 years old) from Chile (n=611) and Colombia (n=358). The body mass index (BMI), waist circumference (WC), waist-to-height ratio (WtHR), MD adherence, PA, ST and cardiorespiratory fitness (CRF) were evaluated. The association of AO and anthropometric variables with lifestyle was estimated through multiple linear regression. To determine the association between AO and lifestyle, a logistic regression and the inclusion of odds ratios (ORs) with 95% confidence intervals (CIs) were used.

RESULTS

Worse CRF in Chilean children were positively correlated with WC. Excess weight in Chilean and Colombian children was positively associated with an unhealthy lifestyle. In Chilean children unhealthy lifestyle was also associated with AO based on WC≥85th percentile and AO based on WtHR≥85th percentile. In Chilean children, excess weight (BMI≥85th percentile) was positively associated with poor MD adherence.

CONCLUSION

AO and excess weight were associated with an unhealthy lifestyle in Latin-American schoolchildren. Interventions to reduce the prevalence of AO should include promoting healthier lifestyle choices (i.e., increasing PA after school, reducing ST and improving CRF).

Can strength exercise affect the muscle oxygen saturation response?

PURPOSE

The objective of the study was to describe and compare the acute response of muscle oxygen saturation (SmO2) and hemoglobin concentration (Hgb) in the vastus lateralis (VL) during resistance exercise protocols until failure.

METHODS

Sixteen males were considered (mean ± SD, age = 36.12 ± 6.40 years). Two familiarization sessions and one evaluation session were carried out where three force protocols were executed in the VL, one of them was isometric load (P1) and two of dynamic load (P2 and P3). SmO2 [%] and Hgb [g/dL] were measured before and after each of these protocols. For P1, three series of 8 s of maximum isometric strength with the rest of 60 s between each set, the average isometric strength (AIS), and the isometric peak strength (IPS) were also recorded. After five minutes, P2 was performed, with an initial load of 40% of AIS. Then, at 30 minutes, P3 was performed considering an initial load of 40% of IPS.

RESULTS

The results suggest (I) minimum levels of SmO2 (66.31 ± 9.38%) and Hgb (12.22 ± 0.55 g/dL) during P2, (II) no significant differences were observed between the average loads of the respective protocols for SmO2 and (III) muscle Hgb differed significantly between rest with P1 and P3.

CONCLUSIONS

Exercises of increasing intensity and of short duration do not significantly modify SmO2. However, Hgb increases substantially compared baseline values.

A new reliable device to assess trunk extensors strength

PURPOSE

This study aimed to examine the reliability of trunk extensor strength assessment with a functional electromechanical dynamometer (FEMD).

METHODS

Thirty-one men performed strength assessment at different velocities (V) (V1 = 0.15 m⋅s-1 , V2 = 0.30 m⋅s-1,V3 = 0.45 m⋅s-1) and range of movement (R) (R1 = 25% cm; R2 = 50% cm), and isometric contraction at 90°. Reliability was obtained through the intraclass correlation coefficient (ICC), typical error (TE), and coefficient of variation (CV).

RESULTS

The absolute reliability provided stable repeatability of the average eccentric strength in the V1R1 condition (CV = 9.52%) and the maximum eccentric strength in V1R1 (CV = 9.63%) and V2R2 (CV = 9.66%). The relative reliability of the trunk extensor's average strength was good (ICC = 0.77-0.83) for concentric and good (ICC = 0.78-0.85) and moderate (ICC = 0.67-0.74) for eccentric contraction. Also, good (ICC = 0.77-0.81) and moderate (ICC = 0.55-0.74) reliability of the maximum strength were obtained for concentric and eccentric contraction. The most reliable manifestation to evaluate the concentric (CV = 11.33%) and eccentric (CV = 9.52%) strength was the average strength in the V1R1 condition and the maximum strength (CV = 10.29%) to isometric assessment. The average concentric strength in the V2R2 condition (r = 0.69) and the maximum eccentric strength in the V1R1 condition (r = 0.65) were the best related to the maximum isometric strength.

CONCLUSIONS

FEMD is a highly reliable device to evaluate trunk extensors strength.

Can strength exercise affect the muscle oxygen saturation response?

Purpose: The objective of the study was to describe and compare the acute response of muscle oxygen saturation (SmO2) and hemoglobin concentration (Hgb) in the vastus lateralis (VL) during resistance exercise protocols until failure. Methods: Sixteen males were considered (mean ± SD, age = 36.12 ± 6.40 years). Two familiarization sessions and one evaluation session were carried out where three force protocols were executed in the VL, one of them was isometric load (P1) and two of dynamic load (P2 and P3). SmO2 [%] and Hgb [g/dL] were measured before and after each of these protocols. For P1, three series of 8 s of maximum isometric strength with the rest of 60 s between each set, the average isometric strength (AIS), and the isometric peak strength (IPS) were also recorded. After five minutes, P2 was performed, with an initial load of 40% of AIS. Then, at 30 minutes, P3 was performed considering an initial load of 40% of IPS. Results: The results suggest (I) minimum levels of SmO2 (66.31 ± 9.38%) and Hgb (12.22 ± 0.55 g/dL) during P2, (II) no significant differences were observed between the average loads of the respective protocols for SmO2 and (III) muscle Hgb differed significantly between rest with P1 and P3. Conclusions: Exercises of increasing intensity and of short duration do not significantly modify SmO2. However, Hgb increases substantially compared baseline values.

Grip power test: A new valid and reliable method for assessing muscle power in healthy adolescents

The assessment of the strength and muscle mass of the hand-finger segment are reliable indicators of health and predictors of cardiometabolic risk in the adult population. However, there are no valid and reliable tests to assess the muscle power of this segment in healthy adolescents. The objective of this study was to determine the validity and inter-day reliability of a grip power test (Grip_W test) in healthy adolescents. Twenty-one adolescents (15.61 ± 2.20 years old) were part of the study. All participants were instructed to perform a grip with incremental load sets from 1–10 kg as fast as possible. The validity of the Grip_W test was determined with the load-power curve and linear regression equation. Inter-day reliability considered the coefficient of variation (CV), intra-class correlation coefficient (ICC), and standard error of the mean (SEM). The significance level for all statistical analyses was p < 0.05. The parabola in the load-power curve for both hands showed normality for the Grip_W test. In addition, the analysis showed a CV = 4.63% and ICC = 1.00 for the right hand, while the left hand showed a CV = 3.23% and ICC = 1.00. The Grip_W test proved to be valid and reliable for assessing gripping muscle power functionally and unilaterally in healthy adolescents.

The Effects of Two Different Concurrent Training Configurations on Markers of Metabolic Syndrome and Fitness in Women With Severe/Morbid Obesity: A Randomised Controlled Trial

Concurrent training (CT), characterised by combining both aerobic and resistance training modalities within the same session, is recognised to improve metabolic syndrome (MetS) markers, but little is known about the effects of different configurations (i.e., order) of these exercise modalities on MetS markers and the interindividual responses. The purpose of the present study was to describe the effects, and the interindividual variability, of 20weeks of two CT configurations (i.e., high intensity interval training (HIIT) plus resistance training (RT), compared with RT plus HIIT) in women with severe/morbid obesity. Overall, 26 women with severe/morbid obesity were assigned either to HIIT+RT [n=14, mean and 95%CI, 45.79 (40.74; 50.83) or RT+HIIT (n=12), 33.6 (25.30; 41.79) years]. MetS-related outcomes were waist circumference (WC, cm), systolic (SBP, mmHg) and diastolic (DBP, mmHg) blood pressure, high-density lipoprotein cholesterol (HDL-c), triglycerides (Tg), and fasting plasma glucose (FPG). Secondary outcomes were other anthropometrics, body composition, lipids, muscle strength, and the six-minute walk test (6Mwt). There were significant differences in the prevalence of nonresponders (NRs) only for WC comparing HIIT+RT 2 (18.1%) vs. RT+HIIT group 5 (50.0%), p<0.0001, but not for SBP 4 (27.2%) vs. 4 (40.0%), DBP 8 (72.7%) vs. 7 (70.0%), FPG 8 (72.7%) vs. 9 (90.0%), HDL-c 7 (63.6%) vs. 8 (80.0%), and Tg 7 (63.6%) vs. 8 (80.0%), all p>0.05. Additionally, the RT+HIIT group showed significant reductions in WC (∆ –3.84cm, p=0.015), SBP (∆ –8.46mmHg, p=0.040), whereas the HIIT+RT group elicited significant reductions only in SBP (∆ –8.43mmHg, p=0.022). The HIIT+RT promoted a lower prevalence of NRs than the RT+HIIT configuration on WC, and overall, there were slightly more beneficial training-induced effects on markers of MetS in the RT+HIIT group compared to the HIIT+RT group.

Isokinetic force-power profile of the shoulder joint in males participating in CrossFit training and competing at different levels

Background

As participants who engage in CrossFit training and competition perform a large volume of high intensity overhead activities, injuries to the shoulder are one of the most common in this sport. Previous research in other sports has indicated that the isokinetic force power profile of the shoulder joint (IPSJ) rotator muscles may assist in the prediction of shoulder injury.

Aim

Therefore, the objective of this study was to determine the IPSJ in males engaged in CrossFit training at different competitive levels.

Methods

In a cross-sectional study design, participants (age, 24.1 ± 2.7 years) classified as ‘beginner’ (n = 6), ‘intermediate’ (n = 7) or ‘advanced’ (n = 9) provided informed consent to participate in this study. The IPSJ assessment involved rotational and diagonal movements, including internal and external shoulder rotator muscles, at both 180°.s⁻¹ and 300°.s⁻¹. The variables analysed were peak torque/body mass (%), mean power (W) and the external/internal peak torque/body mass ratio (%). A Kruskal–Wallis test was used to compare the IPSJ of the three groups, with Dunn’s test used for post-hoc analysis. The alpha level was set at p < 0.05.

Results

The IPSJ showed greater torque and power values in those who competed at the advanced level as compared to those at a lower competitive level (i.e. intermediate, beginner). This was observed mainly for the internal rotation and internal diagonal movements at both 180°.s⁻¹ and 300°.s⁻¹. However, such differences between competitive levels were, in general, absent for the external rotation and external diagonal movements. Moreover, the participants from the advanced competitive level exhibited an imbalance of peak torque between the muscles responsible for the external–internal rotational and external-internal diagonal movements of the shoulder (i.e. peak torque external/internal ratio <66%), particularly in the dominant shoulder.

Conclusion

These findings suggest greater development of the shoulder internal rotators and a higher probability of shoulder injury in CrossFit athletes at the advanced competitive level. Based on these results, participants engaged in CrossFit training and competition may wish to increase the volume of training for the shoulder external rotator muscles to complement the large increases in shoulder internal rotator strength that occur as a part of their regular training regimes.

Selective Attention and Concentration Are Related to Lifestyle in Chilean Schoolchildren

The objective of this investigation was to determine the association between selective attention and concentration with physical fitness (i.e., cardiorespiratory fitness (CRF), V˙O_2max, the standing long jump test (SLJ) and handgrip muscle strength (HGS)), lifestyle parameters (i.e., physical activity (PA) level, screen time (ST), sleep duration and food habits) and anthropometric measures (i.e., body mass index (BMI) and waist circumference (WC)) among Chilean schoolchildren. Two hundred and forty-eight schoolchildren (137 boys, 111 girls, 11.80 ± 1.17 and 11.58 ± 1.09 years, respectively) participated. Selective attention, concentration and lifestyle (PA, ST, sleep duration and Mediterranean diet (MD) adherence) were determined using a standard questionnaire. CRF, SLJ, HGS and anthropometric indicators (BMI and WC) were also measured. Selective attention showed a positive association with MD adherence score (β; 5.012, p = p < 0.05). Concentration was linked inversely to ST (β; −5.498, p = p < 0.05). Likewise, concentration presented a positive association with MD adherence (β; 2.904, p = p < 0.05). In conclusion, children’s lifestyles are related to the selective attention and concentration of children; therefore, promoting healthy habits could be a cost-effective strategy in the promotion of cognitive development, as it relates to selective attention and concentration.

Absolute Reliability and Concurrent Validity of Hand-Held Dynamometry in Shoulder Rotator Strength Assessment: Systematic Review and Meta-Analysis

The purpose of this study is to establish the absolute reliability between hand-held dynamometers (HHDs) and concurrent validity between HHDs and isokinetic dynamometers (IDs) in shoulder rotator strength assessment. The Medline, CINAHL, and Central databases were searched for relevant studies up to July 2020. Absolute reliability was determined by test–retest studies presenting standard error of measurement (SEM%) and/or minimal detectable change (MDC%) expressed as percentage of the mean. Studies considering intra-class correlation coefficient (ICC) between IDs and HHDs were considered for concurrent validity. The risk of bias and the methodological quality were evaluated according to COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN). Thirteen studies were included in the meta-analysis. Shoulder internal rotator strength assessment MDC% was 0.78%, 95% confidence interval (CI) −5.21 to 3.66, while shoulder external rotators MDC% was 3.29%, CI −2.69 to 9.27. ICC between devices was 0.94, CI (0.91 to 0.96) for shoulder internal rotators and 0.92, IC (0.88 to 0.97) for shoulder external rotators. Very high correlation was found for shoulder rotator torque assessment between HHDs and IDs. The COSMIN checklist classified the selected studies as adequate and inadequate.

Syndrome Metabolic Markers, Fitness and Body Fat Is Associated with Sleep Quality in Women with Severe/Morbid Obesity

Background: Sleep is an important modulator of neuroendocrine function and glucose metabolism. Poor sleep quality is related to metabolic and endocrine alterations, including decreased glucose tolerance, decreased insulin sensitivity, and increased hunger and appetite. Objective: The aim of the present study was to determine the association between sleep quality with metabolic syndrome (MetS) markers, fitness and body fat of women with severe/morbid obesity. Methods: This cross-sectional study included 26 women with severe/morbid obesity. Fasting plasma glucose (FPG), high-density lipids (HDL-c), triglycerides (TGs), and the metabolic outcomes total cholesterol (Tc) and low-density lipids (LDL-c), systolic (SBP) and diastolic blood pressure (DBP), body composition and fitness were measured. Results: Poor sleep quality showed a positive association with body fat (%) ≥ 48.2 (OR; 8.39, 95% CI; 1.13–62.14, p = 0.037), morbid obesity (OR; 8.44, 95% CI; 1.15–66.0, p = 0.036), glucose ≥ 100 mg/dL (OR; 8.44, 95% CI; 1.15–66.0, p = 0.036) and relative handgrip strength ≤ 0.66 (OR; 12.2, 95% CI; 1.79–83.09, p = 0.011). Conclusion: sleep quality is associated with health markers in women with severe/morbid obesity.

Test-retest reliability of a functional electromechanical dynamometer on swing eccentric hamstring exercise measures in soccer players

Background

The use of a functional electromechanical dynamometer (FEMD) has been proposed as a valid and effective tool to evaluate specific movement patterns. The aim of this study was to determine the reliability of FEMD on swing eccentric hamstring exercise (SEHE) measures in soccer players.

Methods

Nineteen federated male soccer players (20.74 ± 4.04 years) performed the SEHE at three different isokinetic velocities (20–40–60 cm/s). These evaluations were conducted in four sessions, two for familiarization and two for registration. The average and maximum load (N) of the three isokinetic velocities was calculated from the values obtained from the FEMD (Dynasystem^®, Bangalore).

Results

The main results of this research showed that the reliability was high for the average load in the condition of 40 cm/s, presenting the highest ICC value (0.94). For maximum load, reliability was high in the condition of 20 cm/s. The manifestation of the most reliable load was the maximum load (ICC = 0.91–0.87).

Conclusions

FEMD (Dynasystem^®, Bangalore) is a reliable device to evaluate the eccentric strength of the hamstring muscles in soccer players.

Speed and throwing the ball are related to jump capacity and skeletal muscle mass in university basketball players

BACKGROUND

Speed and throw ball in basketball players are determinant skills for basketball performance. The purpose of this study was to determinate the relationship between speed and throw the ball with jump capacity and body composition in university basketball players.

METHODS

A comparative descriptive study with transversal design and a quantitative approach was performed. Seventeen male University basketball players (age = 23.60±3.45 years, height = 180.41±7.99 cm and Body Mass = 86.48±20.07 Kg) completed the following test: throwing the ball (m/s), handgrip strength (kg), speed 5-20 m (i.e., with and without the ball), jumping and reactive strength. Likewise, anthropometric variables and body composition were evaluated.

RESULTS

A very high correlation was found between the throw ball and the skeletal muscle mass (r=0.810, P<0.001) dominant handgrip strength (r=0.709, P<0.001) and non-dominant handgrip strength (r=0.610, P<0.01). The throw ball reported association with skeletal muscle mass (r2=0.67, P<0.001, 67% of the variance). Significant differences were found in speed with and without the ball at 10 m (P=0.003, ES=-0.854), 15 m (P=<001, ES=-1.548) and 20 m (P=<001, ES=-1.644). The speed of displacement without ball correlated high with the countermovement jump (CMJ) (r=-0.530, P≤0.05) Abalakov (r=-0.586, P≤0.05) and Drop Jump (DJ) (r=-0.685, P≤0.01) in the first 5 m.

CONCLUSIONS

The speed and throwing of the ball are associated with jumping capacity and skeletal muscle mass. Therefore, it is necessary to work these capacities in the university basketball player to improve performance.

Lifestyle mediates the relationship between self-esteem and health-related quality of life in Chilean schoolchildren

A healthy lifestyle, including food habits, physical activity (PA) and screen time (ST), is an important factor for well-being. The main purpose of this study was to analyze the association between lifestyle (i.e., PA, ST and food habits), self-esteem and health-related quality of life (HRQoL). A second objective was to determine the association between self-esteem with HRQoL, considering the mediating effect of lifestyle. A descriptive and cross-sectional study was performed, involving both girls (n = 282, 11.86 ± 0.82 years) and boys (n = 352, 12.02 ± 0.87 years). Lifestyle, self-esteem, HRQoL and anthropometrics parameters were evaluated. The study reported that self-esteem (β; 0.04, P = 0.49) and PA (β; 1.15, P < 0.001) had positive association with HRQoL. By contrast,ST was linked in an inverse way to HRQoL (β; -1.82,, P < 0.001). According to the second objective, self-esteem had a significant association with HRQoL (total effect = 0.48, p < 0.01), and ST mediated this association negatively, instead, PA and food habits positively mediated this association. In conclusion, self-esteem presented association with HRQoL and lifestyle mediates this relationship positively (PA, MD adherence) and negatively (ST). Therefore, promoting healthy lifestyle among children should be a target of community- and school-based interventions to promote well-being.

The association between modifiable lifestyle behaviour in Latin-American schoolchildren with abdominal obesity and excess weight. A comparison of Chile and Colombia

OBJECTIVE

The purpose was to determine the association of lifestyle (i.e., Mediterranean diet [MD] adherence, physical activity [PA], screen time [ST]) and fitness with abdominal obesity (AO) and excess weight in the Chilean and Colombian schoolchildren.

RESEARCH METHODS & PROCEDURES

This cross-sectional study included 969 schoolchildren, girls (n=441, 5.24±0.80 years old) and boys (n=528, 5.10±0.78 years old) from Chile (n=611) and Colombia (n=358). The body mass index (BMI), waist circumference (WC), waist-to-height ratio (WtHR), MD adherence, PA, ST and cardiorespiratory fitness (CRF) were evaluated. The association of AO and anthropometric variables with lifestyle was estimated through multiple linear regression. To determine the association between AO and lifestyle, a logistic regression and the inclusion of odds ratios (ORs) with 95% confidence intervals (CIs) were used.

RESULTS

Worse CRF in Chilean children were positively correlated with WC. Excess weight in Chilean and Colombian children was positively associated with an unhealthy lifestyle. In Chilean children unhealthy lifestyle was also associated with AO based on WC≥85th percentile and AO based on WtHR≥85th percentile. In Chilean children, excess weight (BMI≥85th percentile) was positively associated with poor MD adherence.

CONCLUSION

AO and excess weight were associated with an unhealthy lifestyle in Latin-American schoolchildren. Interventions to reduce the prevalence of AO should include promoting healthier lifestyle choices (i.e., increasing PA after school, reducing ST and improving CRF).

Isokinetic Trunk Strength in Acute Low Back Pain Patients Compared to Healthy Subjects: A Systematic Review

BACKGROUND

The purpose of this systematic review was to: (I) determine the quality of evidence from studies assessing trunk isokinetic strength in subjects with acute low back pain (ALBP) compared to healthy subjects and (II) establish reference values of isokinetic trunk strength in subjects with ALBP.

METHODOLOGY

Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) statements were followed using keywords associated with trunk, strength and low back pain. Four databases were used: PubMed, Web of Science, Scopus and SPORTDiscus. Methodological quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS).

RESULTS

A total of 1604 articles were retrieved, four included in this review. All were evaluated as high risk of bias (Rob). Due to the high Rob and the diversity of protocols, instruments and variables used, it was not possible to determine reference values for subjects with ALBP, we can only establish a range of flexion peak torque (PT) between 175.1 and 89.7 Nm at 60°/s and between 185 and 81.5 Nm at 120°/s, and for extension PT between 240.0 and 91.5 Nm at 60°/s and between 217.5 and 69.2 Nm at 120°/s in subjects with ALBP.

CONCLUSIONS

Due to the low quality of the evidence and the diversity of protocols used when measuring trunk isokinetic strength, it is necessary to carry out new high-quality research to establish reference values of trunk strength in subjects with ALBP.

Sustainable Development Goals and Physical Education. A Proposal for Practice-Based Models

The Sustainable Development Goals (SDGs) is a global strategy that aims to obtain a more equitable and just world. These objectives are organized into 17 SDGs, detailing 169 targets. Different international institutions have emphasized the relevance of education to developing citizens who contribute to achieving the SDGs for 2030. However, a review focused on physical education (PE) has yet to be performed. Therefore, the objective of this work is two-fold. First, to analyze and select the specific SDGs that can be implemented in the area of physical education. Second, to relate these specific goals to the different models based on physical education practices. This review showed how three institutional documents have previously related sport, physical exercise, and physical education to specific SDGs. Based on the search done, this review article selects those goals that could be integrated into the educational context through physical education. The bibliographic and critical analysis in this research shows that of the 169 specific goals proposed in the SDGs, only 24 could be worked on in physical education. Upon completion of the analysis, a proposal for the relationship between the practice-based models and these 24 goals is presented. The contributions made in this paper will allow teachers to establish links between PE sessions and SDGs while raising awareness to develop students who contribute to a more sustainable world.

Effect of different self-selected walking speeds in leveling of body center of mass, mechanical work and energy in healthy children

PURPOSE

The aim of the study was to analyze the general kinematics of the cycle, leveling of the center of mass and inverted pendulum model in school-age children when they walk at three different auto-selected speeds.

METHODS

The kinematics of walking cycle, angular actions that contribute to reducing the vertical displacement of body center of mass (pelvis, hip, knee and ankle) and pendulumlike determining variables (mechanical work, pendulum-like recovery and congruity percentage), were analyzed in children for three different self-selected speeds. Differences for each variable with the speed were tested by ANOVA with Bonferroni post-hoc analysis. Omega squared (ω²) was calculated for the values of the effect sizes.

RESULTS

None of the angular variables associated with the leveling of the vertical trajectory of body center of mass changed. Likewise, recovery and congruity percentage presented values similar to those obtained in previous studies and did not show significant changes with the speeds.

CONCLUSIONS

Nevertheless, changes in horizontal mechanical work and cycle phases, indicate that at some point during the cycle the mechanical energy transfer may have been affected for speed changes. Our results warn about the implication that small changes in the speed during functional evaluations of gait in children may have.

INFLUENCE OF MAXIMAL ISOMETRIC STRENGTH ON 20-METER SPRINT TIME

ABSTRACT Introduction The squat is an exercise that is widely used for the development of strength in sports. However, considering that not all sports gestures are vertical, it is important to investigate the effectiveness of propulsive force stimuli applied in different planes. Objective The main purpose of this study was to determine the influence of maximum isometric force (MIF) exerted on starting blocks over performance in 5, 10 and 20-meter sprints. Methods Seven high-level male sprinters (mean age ± SD = 28 ± 5.77 years) participated in this study. The variables were: a) MIF in squats and on starting blocks (measured using a functional electromechanical dynamometer [FEMD]), b) time in 5, 10 and 20-m sprints and c) jump height (measured by the squat jump test). For data analysis, a Pearson correlation was performed between the different variables. The criteria for interpreting the strength of the r coefficients were as follows: trivial (<0.1), small (0.1−0.3), moderate (0.3−0.5), high (0.5−0.7), very high (0.7−0.9), or practically perfect (>0.9). The level of significance was p < 0.05. Results There was very high correlation between MIF exerted on starting blocks and performance in the first meters of the sprint (5-m: r = -0.84, p = 0.01). However, there was small correlation between MIF in squats and performance in the first meters of the sprint (5-m: r = -0.22, p < 0.62). Conclusion The MIF applied on starting blocks correlates very high with time in the first meters of the sprint in high-level athletes. In addition, the use of the FEMD provides a wide range of possibilities for evaluation and development of strength with a controlled natural movement. Level of evidence IV; Prognostic Studies - Case series.

Effect of different self-selected walking speeds in leveling of body center of mass, mechanical work and energy in healthy children

Purpose: The aim of the study was to analyze the general kinematics of the cycle, leveling of the center of mass and inverted pendulum model in school-age children when they walk at three different auto-selected speeds. Methods: The kinematics of walking cycle, angular actions that contribute to reducing the vertical displacement of body center of mass (pelvis, hip, knee and ankle) and pendulumlike determining variables (mechanical work, pendulum-like recovery and congruity percentage), were analyzed in children for three different self-selected speeds. Differences for each variable with the speed were tested by ANOVA with Bonferroni post-hoc analysis. Omega squared (ω2 ) was calculated for the values of the effect sizes. Results: None of the angular variables associated with the leveling of the vertical trajectory of body center of mass changed. Likewise, recovery and congruity percentage presented values similar to those obtained in previous studies and did not show significant changes with the speeds. Conclusions: Nevertheless, changes in horizontal mechanical work and cycle phases, indicate that at some point during the cycle the mechanical energy transfer may have been affected for speed changes. Our results warn about the implication that small changes in the speed during functional evaluations of gait in children may have.

Effect of High-Intensity Interval Training on Body Composition, Cardiorespiratory Fitness, Blood Pressure, and Substrate Utilization During Exercise Among Prehypertensive and Hypertensive Patients With Excessive Adiposity

Regular exercise training is a recognized lifestyle strategy to lower resting blood pressure (BP), but little is known about substrate metabolism in population with high BP. Thus, the purpose of this study was to investigate the effects of 16-weeks of HIIT on body composition, BP, cardiorespiratory fitness by V.O_2max, and substrate utilization during exercise among prehypertensive and hypertensive patients with excessive adiposity. We also aimed to test the potential association between changes in cardiorespiratory fitness, substrate utilization during exercise and BP. Forty-two physically inactive overweight/obese participants participated in 16-weeks of HIIT intervention. The HIIT frequency was three times a week (work ratio 1:2:10, for interval cycling: rest period: repeated times; 80–100% of the maximum heart rate). Groups were distributed based on their baseline BP: HIIT-hypertensive (H-HTN: age 47.7 ± 12.0 years; body mass index [BMI] 30.3 ± 5.5 kg/m²; systolic [SBP]/diastolic BP [DBP] 151.6 ± 10/81.9 ± 4.2 mmHg), HIIT-pre-hypertensive (H-PreHTN: age 37.6 ± 12.0 years; BMI 31.9 ± 5.3 kg/m²; SBP/DBP 134.4 ± 3.2/74.9 ± 7.0 mmHg), and a normotensive control group (H-CG: age 40.7 ± 11.0 years; BMI 29.5 ± 4.2 kg/m²; SBP/DBP 117.0 ± 6.2/72.4 ± 4.1 mmHg). Anthropometry/body composition, BP, and metabolic substrate utilization during exercise (fat [FATox], carbohydrate [CHOox] oxidation, respiratory exchange ratio [RER], and V.O_2max), were measured before and after the 16-week HIIT intervention. Adjusted mixed linear models revealed a significant improved in V.O_2max were + 3.34 in the H-CG, + 3.63 in the H-PreHTN, and + 5.92 mL⋅kg^–1⋅min^–1, in the H-HTN group, however, the Time × Group interaction were not significant (p = 0.083). All the exercise types induced similar decreases on SBP (−8.70) in the H-HTN, (−7.14) in the H-CG, and (−5.11) mmHg in the H-PreHTN, as well as DBP levels (−5.43) mmHg in H-CG group (p = 0.032 vs. H-HTN group). At 16-week, no significant correlations were noted for the changes of blood pressure, cardiorespiratory fitness or exercise metabolism substrates outcomes. In conclusion, our results suggest that a 16-week HIIT-intervention improved V.O_2max and blood pressure BP, but these changes are independent of substrate utilization during exercise in normotensive and hypertensive participants with excessive adiposity.

Reliability of a standing isokinetic shoulder rotators strength test using a functional electromechanical dynamometer: effects of velocity

Background

The evaluation of the force in internal rotation (IR) and external rotation (ER) of the shoulder is commonly used to diagnose possible pathologies or disorders in the glenohumeral joint and to assess patient’s status and progression over time. Currently, there is new technology of multiple joint isokinetic dynamometry that allows to evaluate the strength in the human being. The main purpose of this study was to determine the absolute and relative reliability of concentric and eccentric internal and external shoulder rotators with a functional electromechanical dynamometer (FEMD).

Methods

Thirty-two male individuals (21.46 ±  2.1 years) were examined of concentric and eccentric strength of shoulder internal and external rotation with a FEMD at velocities of 0.3 m s⁻¹ and 0.6 m s⁻¹. Relative reliability was determined by intraclass correlation coefficients (ICC). Absolute reliability was quantified by standard error of measurement (SEM) and coefficient of variation (CV). Systematic differences across velocities testing circumstances, were analyzed with dependent t tests or repeated-measures analysis of variance in case of 2 or more than 2 conditions, respectively.

Results

Reliability was high to excellent for IR and ER on concentric and eccentric strength measurements, regardless of velocity used (ICC: 0.81–0.98, CV: 5.12–8.27% SEM: 4.06–15.04N). Concentric outcomes were more reliable than eccentric due to the possible familiarization of the population with the different stimuli.

Conclusion

All procedures examined showed high to excellent reliability for clinical use. However, a velocity of 0.60 m s⁻¹ should be recommended for asymptomatic male patients because it demands less time for evaluation and patients find it more comfortable.

Instrumental validity and intra/inter-rater reliability of a novel low-cost digital pressure algometer

Background

Pain assessment is a key measure that accompanies treatments in a wide range of clinical settings. A low-cost valid and reliable pressure algometer would allow objective assessment of pressure pain to assist a variety of health professionals. However, the pressure algometer is often expensive, which limits its daily use in both clinical and research settings.

Objectives

This study aimed to assess the instrumental validity, and the intra- and inter-rater reliability of an inexpensive digital adapted pressure algometer.

Methods

A single rater applied 60 random compressions on a force platform. The pressure pain thresholds of 20 volunteers were collected twice (3 days apart) by two raters. The main outcome measurements were as follows: the maximal peak force (in kPa) and the pressure pain threshold (adapted pressure algometer vs. force platform). Cronbach’s α test was used to assess internal consistency. The standard error of measurement provided estimates of measurement error, and the measurement bias was estimated with the Bland–Altman method, with lower and upper limits of agreement.

Results

No differences were observed when comparing the compression results (P = 0.51). The validity and internal intra-rater consistencies ranged from 0.84 to 0.99, and the standard error of measurement from 0.005 to 0.04 kPa. Very strong (r = 0.73–0.74) to near-perfect (r = 0.99) correlations were found, with a low risk of bias for all measurements. The results demonstrated the validity and intra-rater reliability of the digitally adapted pressure algometer. Inter-rater reliability results were moderate (r = 0.55–0.60; Cronbach’s α = 0.71–0.75).

Conclusion

The adapted pressure algometer provide valid and reliable measurements of pressure pain threshold. The results support more widespread use of the pressure pain threshold method among clinicians.

Poor Sleep Quality Decreases Concurrent Training Benefits in Markers of Metabolic Syndrome and Quality of Life of Morbidly Obese Patients

Background: Sleep quality (SQ) plays a role in multiple activities of daily living, but little is known about its role in concurrent training [CT, high-intensity interval (HIIT) plus resistance training (RT)] adaptations for metabolic syndrome (MetS) and health-related quality of life (HRQoL) markers. The aim of the present study was to determine the effects of a 20-week CT programme on MetS and HRQoL markers according to the SQ of morbidly obese patients. Methods: Twenty-nine morbidly obese patients were allocated to one of two groups: good sleep quality (GSQ, n = 15, 38.07 ± 12.26 years) and poor sleep quality (PSQ, n = 14, 40.79 ± 11.62 years). HRQoL, body mass index, waist circumference (WC), systolic and diastolic blood pressure (SBP and DBP, respectively), and plasma outcomes were measured. Results: The GSQ group reported significant changes (pre- vs. post-intervention) in WC (114.0 ± 3.1 vs. 110.4 ± 3.4 cm, p = 0.012), SBP (137.0 ± 4.3 vs. 125.6 ± 1.8 mmHg, p = 0.006), and HRQoL general health (51.33 ± 21.08 vs. 64.33 ± 16.24, p = 0.020). By contrast, the PSQ group showed significant changes only in SQ (9.00 ± 2.42 vs. 5.36 ± 2.84, p = 0.004). Conclusions: Morbidly obese PSQ patients showed a lower response for improving MetS and HRQoL markers after a 20-week CT programme than GSQ peers. However, there was a greater effect size for decreasing WC and SBP in favour of the GSQ compared with the PSQ group, suggesting that there are limitations to CT benefits on these outcomes in the PSQ group. These results call for more complex future studies.

Depression is associated with lower levels of physical activity, body image dissatisfaction, and obesity in Chilean preadolescents

Mental health during the preadolescent years may be determinant for later periods of life; therefore, the factors that influence it need to be studied deeply. The aim of this study was to determine the association between depressive symptoms with physical activity (PA), body image dissatisfaction and weight status in preadolescents. A total of 269 girls and 329 boys (age 12.02 ± 0.98 years) were included in this study. Body mass index (BMI), waist circumference, body image dissatisfaction, PA and depressive symptoms were assessed. The PA reported an inverse association with depression in girls (β:-2.12, P < 0.0001) and boys (β:-1.13, P = 0.001). Instead, BMI in girls (β: 1.00, P < 0.0001) and boys (β: 0.70, P < 0.0001), and body image dissatisfaction in girls (β: 0.05, P = 0.017) and boys (β: 0.04, P = 0.003) reported positive association with depression. In the same way, depression was associated with obesity (odds ratio [OR] = 2.05, P = 0.020), but, the boys had higher risk (OR = 18.4, P < 0.001) than girls. In conclusion, depression in Chilean preadolescents presented association with low levels of PA, obesity and body image dissatisfaction. Therefore, schools should target and promote PA to improve psychological and physical health in preadolescents, which may reduce the future burden of mental illness.

Behavior of the muscle quality index and isometric strength in elderly women

This study aimed (I) to compare the muscle quality index (MQI) and the isometric hip strength between younger and older women, and (II) to determine the relationship of the MQI with the sit-to-stand test (STS) and isometric hip strength in younger and older women. Twenty-eight elderly women (age= 66.2 ± 5.6 years) and twenty younger women (21.2 ± 2.2 years) participated in the study. The following dependent variables were measured: MQI, STS, body composition, and the peak isometric strength of the hip (PF) which was also normalized using three different methods (PF/Body Mass, PF/Fat-Free Mass, and PF/Body Mass^0,335). Older women presented a lower PF in hip flexion, extension and external rotation regardless of the method of normalization (p < 0.001), but the PF of hip abductors and internal rotators was higher for older women (p < 0.05). No significant differences were found in the MQI between older and younger women (p = 0.443). The MQI was negatively correlated with the time in the STS in older women (r = -0.706, p < 0.001) and younger women (r = -0.729, p < 0.001), while the correlations of MQI with isometric hip strength were weaker in older women (r range: -0.082 - 0.556) and younger women (r range: -0.020 - 0.309). MQI is a clinical and practical tool to assess the muscular power of the lower extremities.

Influence of Grip Width and Anthropometric Characteristics on the Bench-Press Load-Velocity Relationship

PURPOSE

To compare the load-velocity (L-V) relationship between bench-press exercises performed using 4 different grip widths, to determine the association between the anthropometric characteristics and L-V profile, and to explore whether a multiple linear-regression model with movement velocity and subjects' anthropometric characteristics as predictor variables could increase the goodness of fit of the individualized L-V relationship.

METHODS

The individual L-V relationship of 20 men was evaluated by means of an incremental loading test during the bench-press exercise performed on a Smith machine using narrow, medium, wide, and self-selected grip widths. Simple and multiple linear-regression models were performed.

RESULTS

The mean velocity associated with each relative load did not differ among the 4 grip widths (P ≥ .130). Only body height and total arm length were correlated with the mean velocity associated with light and medium loads (r ≥ .464). A slightly higher variance of the velocity attained at each relative load was explained when some anthropometric characteristics were used as predictor variables along with the movement velocity (r2 = .969 [.965-.973]) in comparison with the movement velocity alone (r2 = .966 [.955-.968]). However, the amount of variance explained by the individual L-V relationships was always higher than with the multiple linear-regression models (r2 = .995 [.985-1.000]).

CONCLUSIONS

These results indicate that the individual determination of the L-V relationship using a self-selected grip width could be recommended to monitor relative loads in the Smith machine bench-press exercise.