Dominant Limb Research Articles

Humeral retroversion, shoulder range of motion, and functional mobility in striking martial arts athletes

The aim of the study was to evaluate humeral retroversion, shoulder range of motion, and functional mobility in karatekas, boxers, kickboxers, and mixed martial arts fighters. This study investigated adaptive alterations in striking martial arts. Forty young healthy participants took part in the study. 20 people who professionally trained in boxing, kickboxing, karate, and Mixed Martial Arts (MMA) fighters (age: 23.5 ± 7.1, age of participation 11.8 ± 3.65, sports experience 9.55 ± 5.13, body weight 79.2 ± 13 kg, BMI 24.4 ± 3.3) were qualified for the group of athletes. 20 people (age: 27 ± 5.5, body weight 79.4 ± 7.4, BMI 24.5 ± 1.2) were included in the control group, who had no previous experience with striking combat sports. An ultrasound device and a digital inclinometer were used for the examination of the humeral retroversion angle. The mobility of the shoulder was also tested using the Functional Movement Screen (FMS). There was a significant (p < 0.001, r = 0.92) asymmetry between the dominant and non-dominant limb in the humeral retroversion angle in the athlete group. A statistically significant moderate correlation (p < 0.05) was found between the value of the retroversion angle and the range of motion of passive and active internal rotation, and external rotation, and the shoulder mobility in the FMS test. However, there were no statistically significant differences (p > 0.05) in the humeral retroversion angles between groups. The striking martial arts athletes do not exhibit significant differences in humeral retroversion compared to non-athletes, however they display notable asymmetry between limbs, with higher values in the non-dominant arm. Additionally, the observed correlation between humeral retroversion and shoulder rotation range of motion highlights the potential impact of humeral retroversion on upper limb performance and injury risk.

Implications for fall efficacy strategies on center of pressure and center of gravity sway distances in adults with chronic low back pain.

Although chronic low back pain (LBP) is a complex condition often associated with altered motor control and compensatory postural adjustments, existing literature provides inconsistent reports on the underlying control mechanisms for maintaining balance. This study aimed to compare differences in sway distances between the center of pressure (COP) and the center of gravity (COG), while considering limb dominance, in adults with and without LBP. There were 26 subjects with LBP and 39 control subjects who performed three repeated unilateral standing tasks on a force platform. Outcome measures included the sway distances between COP and COG in the anteroposterior (AP) and mediolateral (ML) directions, as well as the results of the fall efficacy scale (FES). A significant group interaction was demonstrated on limb dominance and direction for the sway distance (F = 5.46, p = 0.02). Specifically, the third trial in the ML direction while standing on the dominant limb indicated a significant difference in COP-COG sway distance (t = -2.30, p = 0.01). When FES scores were used as a covariate, a significant three-way interaction (dominance x direction x trial) was found (F = 4.06, p = 0.04). Although no significant group interaction was observed for dominance, direction, and trial, the LBP group demonstrated an ability to leverage fall efficacy following repeated trials to reduce ML balance deficits. Clinicians should consider neuromuscular control and limb dominance when developing fall efficacy strategies for postural adaptations in adults with LBP.

Task demands modulate distal limb handedness: A comparative analysis of prehensile synergies of the dominant and non-dominant hand

The dynamic dominance hypothesis of handedness suggests a distinct control strategy for the dominant and the non-dominant limb. The hypothesis demonstrated that the dominant proximal limb is tuned for optimal trajectory control while the non-dominant limb is tuned for a stable grasp. Whether the hypothesis can be extended to distal segments like fingers, especially during a five-fingered grasp, has been studied little. To examine this, an attempt was made to compare the prehensile synergies and force magnitudes of the dominant (DOM) and non-dominant hands (NDOM) during a 5-fingered prehension task. Participants traced a trapezoidal and inverse trapezoidal path with their thumbs on a sliding platform while holding a handle in static equilibrium. The DOM hand performed better only in the inverse trapezoid condition, exhibiting a reduced grip force and increased synergy index aligning with the dynamic dominance hypothesis. No differences were observed for the trapezoid condition, likely due to reduced task demands. The study also explored changes in anticipatory synergy adjustments between the DOM and NDOM hands, but the differences were non-significant. Overall, the DOM hand demonstrated better force coordination than the NDOM hand in challenging conditions. Applications of the study in the objective assessment of handedness were proposed.

Effects of metformin phonophoresis and exercise therapy on pain, range of motion, and physical function in chronic knee osteoarthritis: randomized clinical trial

BackgroundKnee osteoarthritis (KOA) is a common musculoskeletal disorder. Therapeutic ultrasound (US) is a safe and effective treatment for KOA. It relieves knee pain and enhances function. Metformin (MF) regulates chondrocytes, hence providing chondroprotection. Furthermore, it efficiently reduces knee articular cartilage degeneration and retards the progression of osteoarthritis. However, the localized administration of MF by phonophoresis for KOA has yet to be studied.PurposeTo assess the possible effects of metformin phonophoresis (MFPH) plus exercise therapy (EX) compared to MFPH alone or the US on knee pain, function, and range of motion (ROM) in chronic KOA patients.MethodsSeventy-eight patients with unilateral mild to moderate chronic KOA were included. Patients were randomly assigned to three groups: group A (MFPH + EX), group B (MFPH alone), and group C (US). The US group used an acoustic-neutral gel, while the MFPH group used a gel containing 1.2% MF. The exercises included hamstring stretches, calf stretches, and knee strengthening exercises. Treatment in the three groups continued for four weeks (three sessions per week). The Visual Analog Scale (VAS), the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and the goniometer were used to assess knee pain, function disability, and ROM, respectively. All measures were recorded before, 2 weeks, and 4 weeks after the intervention in all groups. Multivariate Analysis of Variance (MNOVA) was performed to compare the effects within and between groups for knee ROM and function disability. The Kruskal-Wallis test and the Friedman test analyzed the pain intensity.ResultsWhen the baseline patient characteristics were compared, there were no significant differences in means of age, gender, body mass index (BMI), or lower limb dominance across the three groups (p > 0.05). After 4 weeks of intervention, clinical outcomes significantly improved in all three groups (p < 0.05). However, patients in the MFPH + EX group improved significantly in all outcomes compared to the MFPH and US groups (p < 0.05).ConclusionPost-treatment results showed a statistically and clinically significant improvement in pain intensity, knee ROM, and function in the MFPH group; however, combining MFPH with exercises is more beneficial in reducing KOA symptoms.Trial registrationClinical Trial Registry at (pactr.samrc.ac.za) database.NO: PACTR202311507335269. Date: November 9, 2023 (retrospectively registered).

Improvements in upper extremity isometric muscle strength, dexterity, and self-care independence during the sub-acute phase of stroke recovery: an observational study on the effects of intensive comprehensive rehabilitation.

Stroke often impairs upper extremity motor function, with recovery in the sub-acute phase being crucial for regaining independence. This study examines changes in isometric muscle strength, dexterity, and self-care independence during this period, and evaluates the effects of a comprehensive intensive rehabilitation (COMIRESTROKE). Individuals in sub-acute stroke recovery and age- and sex-matched controls were assessed for pre- and post-rehabilitation differences in primary outcomes (grip/pinch strength, Nine Hole Peg Test [NHPT], Action Research Arm Test [ARAT]). COMIRESTROKE's effects on primary and secondary outcomes (National Institute of Health Stroke Scale [NIHSS], Modified Rankin Scale [MRS], Functional Independence Measure [FIM]) were evaluated. Outcomes were analyzed for dominant and non-dominant limbs, both regardless of impairment and with a focus on impaired limbs. Fifty-two individuals with stroke (NIHSS 7.51 ± 5.71, age 70.25 ± 12.66 years, 21.36 ± 12.06 days post-stroke) and forty-six controls participated. At baseline, individuals with stroke showed significantly lower strength (dominant grip, key pinch, tip-tip pinch, p adj < 0.05), higher NHPT scores (p adj < 0.05), and lower ARAT scores (p adj < 0.001). COMIRESTROKE led to improvements in dominant key pinch, non-dominant tip-tip pinch, NHPT, and both dominant and non-dominant ARAT (p adj < 0.05). Notably, non-dominant key pinch improved significantly when considering only impaired hands. Pre- and post-test differences between groups were significant only for ARAT (both limbs), even after adjustment (p adj < 0.05). All secondary outcomes (NIHSS, MRS, FIM) showed significant improvement post-COMIRESTROKE (p adj < 0.001). Individuals with stroke exhibit reduced muscle strength and dexterity, impairing independence. However, comprehensive intensive rehabilitation significantly improves these functions. Data are available from the corresponding author upon request and are part of a sub-study of NCT05323916.

The mediating role of kinesiophobia in pain intensity, physical function, and physical activity level in inflammatory arthritis.

Pain is the main symptom of inflammatory arthritis and it can impair physical functional performance and physical activity level. Some individuals can develop kinesiophobia and experience a vicious circle of worsening health. This study aimed to investigate the association between pain and physical functional performance/physical activity and determine whether kinesiophobia mediates this association. This was a cross-sectional study with individuals diagnosed with inflammatory arthritis (rheumatoid arthritis or spondyloarthritis) treated at a Rheumatology Outpatient Clinic. We assessed pain (Visual Analogue Scale), physical activity (International Physical Activity Questionnaire - long form), kinesiophobia (Tampa Scale for Kinesiophobia), and physical functional performance (Handgrip Strength Dynamometry, 30-second Sit-to-Stand test, Static Muscular Endurance test, and Timed Up and Go test). The mediating effect of kinesiophobia on the relationship between pain intensity and physical functional performance/physical activity was analyzed, and the significance of the mediating effect (kinesiophobia) was tested through a bootstrap approach. Thirty-three individuals with inflammatory arthritis (mean age: 48 ± 12 years) participated in the study. Kinesiophobia mediates the relationship between pain intensity and physical functional performance analyzed by the 30-second Sit-to-Stand test [indirect effect (IE)overall = -0.343, bootstrap 95% confidence interval (CI): -0.698 to -0.002] and by knee flexion at 90º of the dominant limb (IEoverall = -1.55, bootstrap 95% CI: -3.43 to -0.237). In conclusion, pain intensity can affect physical functional performance through kinesiophobia in individuals with inflammatory arthritis.

Prevalence of Asymptomatic Changes in the Groin Region Among Adult Professional Soccer Players and Their Association With Limb Dominance.

To investigate the prevalence of asymptomatic radiologic groin region findings in adult professional soccer players using magnetic resonance imaging (MRI) and examine the influence of age and limb dominance on their occurrences. Cross-sectional trial. Soccer club medical service, private practice. Forty-seven male professional soccer players. Players underwent a groin presigning MRI scan with a magnetic field induction of 1.5 Tesla. Image analysis of their pubic bones was performed according to The Copenhagen Standardized MRI protocol to assess the pubic symphysis and adductor regions of players. The prevalence of various changes in the symphysis, pubic bone, and adjacent areas. Fifty images of pubic bones and adjacent regions (53.2%) highlighted 1 to 4 changes, while another 44 images (46.8%) demonstrated 5 or more changes. The most frequent changes observed in the pubic bone were joint surface irregularities (100%), symphyseal sclerosis (93.6%), pubic bone swelling (56.3%), parasymphyseal high-intensity line (55.3%), fatty infiltration in bone marrow (38.3%), and adductor tendinopathy (34%). When comparing the prevalence of different changes in the dominant and nondominant limbs, no statistically significant differences were found. In adult professional soccer players with no prior groin pain complaints in recent history (12 months), asymptomatic changes are extremely common in the pubic joint and adjacent areas, including those that are very likely to be considered the main cause of pain when investigated in soccer players with groin pain. None of these changes were associated with limb dominance.

Analysis of Spatiotemporal Gait Variables before and after Unilateral Total Knee Arthroplasty

This study aimed (a) to evaluate the spatiotemporal gait variables of total knee arthroplasty (TKA) before (pre-) and after the procedure (post-), and (b) to investigate the influence of the surgical side on these variables. Twenty-one volunteers (13 females and 8 males) participated, undergoing assessments pre-surgery and nine to 12 months post-surgery. Clinical tests indicated significant reductions in knee pain and improvements in active and passive extension post-surgery. TKA resulted in decreased pain, extension deficits, and functional assessments, with lower scores on the WOMAC questionnaire. A gait analysis showed post-surgery improvements in gait speed (5.8%), cycle time (−4.8%), step time (4.4%), double limb support time (−11.1%), step (4.4%) and stride (6.3%) lengths, and step (5.1%) and stride (5.0%) cadences. Comparisons between surgical side and limb dominance indicated significant differences in gait speed, stance, swing and step times, double limb support time, step and stride lengths, and step cadence. The non-dominant limb demonstrated greater improvements across most parameters compared to the dominant limb. These findings emphasize the importance of considering the limb dominance of patients with knee osteoarthritis when evaluating post-TKA function. These conclusions can be helpful for personalized rehabilitation programs, allowing tailored interventions for individuals undergoing knee surgery.

Upper-Extremity physical performance tests in older adults: Reference values, reliability and measurement error

BackgroundPhysical performance tests are reliable tools to assess aspects related to strength, power, and mobility. Unfortunately, few studies were performed with older adults. The main goal of this study was to describe reference values for the Closed Kinetic Chain Upper Extremity Stability Test (CKCUEST) and Upper Quarter Y Balance Test (UQYBT) in older adults and to determine differences based on sex. Reliability and measurement error were also established. MethodsTest-retest design with a sample of 103 older adults. The CKCUEST (number of touches, normalized score, and power) and the UQYBT (reach in the medial, superolateral, and inferolateral direction, total excursion, and the composite score) were performed. The scores on both tests were adjusted using an analysis of covariance model. Reliability was determined using Intraclass Correlation Coefficient and error measurement through Standard Error of Measurement, Smallest Detectable Change, and Bland and Altman Plots. ResultsNormative values were provided. Males presented higher scores than females only in the medial reach of the UQYBT in the dominant limb (p < 0.001). Good reliability was found for the CKCUEST, while good to excellent reliability was found for the UQYBT; with the exception of the superolateral reach in the dominant limb. Absence of systematic error was presented. ConclusionNormative data were provided and differences according to sex were found only in the UQYBT. Results demonstrated good to excellent reliability, except the superolateral reach in the dominant limb. Clinically acceptable absolute reliability values were found.

Investigation of Dynamic Balance, Limb Asymmetry and Flexibility in Jiu-Jitsu Athletes: A Preliminary Exploratory Study

This preliminary exploratory study is the first to thoroughly examine dynamic balance, inter-limb asymmetry, and flexibility in jiu-jitsu athletes, focusing on differences by fighting style, competition level, gender, and limb dominance. A total of 25 jiu-jitsu fighters participated in this cross-sectional study, which used repeated measures to ensure the reliability of the findings. Participants underwent measurements for limb lengths and were assessed for dynamic balance using the Lower and Upper Quarter Y Balance Test (LQYBT and UQYBT) and for flexibility with the Sit and Reach Test (SR). The analysis included evaluating the reliability of these tests, as well as comparing outcomes based on gender, fighting styles, competition levels, and limb dominance. The results showed that the LQYBT and UQYBT tests were reliable (ICC=0.74–0.93). There were no significant differences in dynamic balance and flexibility between different fighting styles. No significant differences were found in balance tests between the dominant and non-dominant limbs, but there were notable inter-limb asymmetries in certain measures. This study provides preliminary insights for coaches and researchers by offering reference values for balance, flexibility, and inter-limb asymmetry in jiu-jitsu athletes. However, future research with larger sample sizes is needed to better understand the differences among subgroups in this sport.

Factors Associated With a Successful Return to Performance After Anterior Cruciate Ligament Reconstruction: A Multiparametric Evaluation in Soccer Players.

Anterior cruciate ligament reconstruction (ACLR) is highly recommended in patients with ACL deficiency who must perform at a high physical level. A combination of functional and psychological outcome measures is necessary to provide a comprehensive evaluation of functional status after successful return to sport after ACLR. To identify factors associated with higher functional outcomes among soccer players who had returned to full sports participation after ACLR. Cohort study; Level of evidence, 3. A total of 168 out of 231 patients who underwent primary unilateral arthroscopic anatomic single-bundle ACLR were available at follow-up. Postoperatively, knee function, generic health outcomes, and psychological impact were assessed using the International Knee Documentation Committee (IKDC), the Knee injury and Osteoarthritis Outcome Score (KOOS), the Lysholm Knee Scoring Scale, the 12-item Short Form Health Survey (SF-12), and the ACL-Return to Sport after Injury scale. After a mean follow-up of 35.5 ± 22.6 months, 85% of soccer players returned to performance. Midfielder position was associated with a better SF-12 Physical Component Summary (PCS) score (P = .013), IKDC (P = .003), total KOOS (P < .001), KOOS Symptoms (P = .004), KOOS Pain (P = .029), KOOS Activities of Daily Living (ADL) (P = .044), KOOS Sport and Recreation (Sport/Rec) (P = .001), KOOS Quality of Life (QoL) (P < .001), and Lysholm score (P = .008). Playing only on natural grass was associated with lower SF-12 PCS scores (P = .003), total KOOS (P = .001), and KOOS Sport/Rec (P = .011). Playing only on artificial turf was associated with lower Lysholm score (P = .018) and total KOOS (P = .014). The contact mechanism was associated with higher IKDC (P = .044) and KOOS QoL (P = .048), and injury affecting the dominant limb was associated with lower SF-12 Mental Component Summary scores (P = .012). Playing at a nonprofessional level was associated with lower total KOOS (P = .028), KOOS Symptoms (P = .002), KOOS ADL (P = .033), and KOOS Sport/Rec (P = .016). Professional soccer players and the midfielder position are associated with better functional scores upon returning to the sport. A history of noncontact ACL injury and playing on a single type of surface are associated with lower functional outcomes upon returning to the sport. Lower mental health scores can be expected after injury of the dominant limb.

Examination of sex differences in fatigability and neuromuscular responses during continuous, maximal, isometric leg extension

Objective.This study examined sex-related differences in fatigability and neuromuscular responses using surface electromyographic (sEMG) and mechanomyographic (sMMG) amplitude (AMP) and frequency (MPF) during fatiguing, maximal, bilateral isometric leg extensions.Approach.Twenty recreationally active males and females with resistance training experience performed continuous, maximal effort, bilateral isometric leg extensions until their force reduced by 50%. Linear mixed effect models analyzed patterns of force, sEMG, and sMMG AMP and MPF responses in the dominant limb. An independent samples t-test compared time-to-task failure (TTF) between sexes.Main Results.There were no significant differences in TTF between males and females. However, males experienced a greater rate of force loss compared to females. Furthermore, sEMG AMP and MPF and sMMG AMP responses followed similar linear trends for both sexes, while sMMG MPF showed non-linear responses with sex-dependent differences.Significance.These data suggest that although TTF was similar, males had a higher rate of force reduction, likely due to greater absolute strength. Furthermore, despite parallel changes in sEMG AMP and MPF, as well as sMMG AMP, the divergent responses observed in sMMG MPF highlight sex-dependent differences in how males and females experience changes in the firing rates of active motor units during sustained maximal contractions.

The Cross-education Effect: Is There An Asymmetrical Transfer Of Strength Between Dominant And Non-dominant Limbs?

The Cross-education Effect: Is There An Asymmetrical Transfer Of Strength Between Dominant And Non-dominant Limbs?

Non-invasive remote ischemic preconditioning for patients with heart failure undergoing cardiac catheterization: a network meta-analysis of randomized controlled trials

ObjectiveThis study aimed to evaluate the efficacy of six non-invasive remote ischemic preconditioning (RIPC) interventions during the nursing care of patients with heart failure (HF) prior to cardiac catheterization.MethodsA comprehensive search of nine Chinese and English online databases was conducted from the date of their inception to June 2023 to identify randomized controlled trials (RCTs) investigating RIPC in patients with HF prior to cardiac catheterization. Two independent investigators screened the articles, extracted data, and assessed their quality. The risk of bias was evaluated using the Cochrane risk-of-bias tool, and a network meta-analysis was conducted using R software.ResultsFour trials involving 511 patients with a low risk of bias were included in the analysis. Six non-invasive RIPC interventions were identified, all demonstrating effectiveness in reducing the incidence of contrast-induced acute kidney injury (CI-AKI). Among these, Intervention F (applying up to 50 mmHg above the resting systolic pressure for 5 min to the dominant leg or upper limb, repeated three times with an 18-minute interval) was deemed optimal, although the timing of the procedure was not specified. Intervention D (applying up to 200 mmHg pressure to the upper limb for 5 min, repeated four times with 5-minute intervals, within 45 min prior to cardiac catheterization, ) was considered suboptimal.ConclusionAlthough Intervention D was recommended as the preferred option, none of the four trials examined its impact on the cardiac function of patients with HF. Large-scale, multi-center RCTs are required, with outcome indicators including cardiac function and the occurrence of CI-AKI, to better understand the therapeutic effects of RIPC on HF and reduce the incidence of CI-AKI. This will provide a more robust foundation for clinical practice.

Pelvic and Lower Limb Kinematics in Individuals With Chronic Low Back Pain During Sit-to-Stand Function: A Cross-Sectional Study

ObjectivesThe aim of this study was to investigate the 3-dimensional movement kinematics of pelvic and lower limb joints in CLBP subjects, compared to healthy individuals, utilizing a functional data analysis (FDA) approach. MethodsIn this study, a 7-camera Qualisys motion capture system was employed to record the kinematics of the pelvic, hip, knee, and ankle joints in 20 patients with low back pain (LBP) and 20 control subjects on both sides during the sit-to-stand motion. An FDA statistical approach was utilized to compare the data collected over time between the 2 groups. The STS task was divided into two distinct phases: the prelift off phase (pre-Lo) and the postlift off phase (post-Lo). ResultsDuring the “pre-Lo phase” of the STS motion, our statistical analysis revealed that the only significant difference between the two groups was a decreased medial rotation (P = .00) in the hip joint position of LBP patients on their dominant side, in comparison to healthy subjects. As for the “post-Lo phase,” the LBP group exhibited a more anterior pelvic tilt position (P = .00) and increased pelvic counterclockwise rotation (P = .03) in the sagittal and transverse planes when compared to the control group. Regarding hip joints, the LBP group demonstrated a more flexed position (indicative of reduced extension) on both the dominant (P = .00) and nondominant (P = .00) sides, coupled with diminished abduction (P = .04) and internal rotation (P = .03) of the hip on the dominant side. In relation to the knee and ankle joints, the results indicated a more adducted knee position (P = .00) and decreased ankle joint flexion (P = .02) on the dominant side in CLBP subjects when compared to the healthy group during the STS motion. ConclusionOur findings indicate that patients with CLBP exhibited distinct kinematic patterns in the pelvic and lower limb joints during the STS motion. These kinematic alterations primarily manifest in the joints of the dominant limb, with most of the differences observed during the second phase (postlift off phase) of the motion. It appears that these changes in pelvic and lower limb joint kinematics should be taken into account when planning future rehabilitation programs for CLBP patients engaged in this task.

The long-term impact of rehabilitation in upper limb plexopathies

The main objective of the research consists in providing evidence that a long-term rehabilitation protocol is favorable for the patient. In adult brachial plexus (BP) palsies, after several surgical attempts, the lack of results in the upper limb’s functionality leads to less compliance to rehabilitation therapy. The upper limb’s functionality of 22 patients with posttraumatic operated chronic BP paresis (either on the right or left, regardless the dominant limb) was assessed retrospectively. The patients were evaluated regarding MRC scaling, dynamometric tests and electroneuromyographic examination. All patients have gone through at least one rehabilitation interval (10 days) after an initial evaluation, and were evaluated again, by same methods, at a second session, at least 6 months later, but no more than one year.. Mild and inconstant improvements were obtained in a total of 9 patients, especially in better dynamometric results and improved amplitudes of motor and sensory action potentials. The electrodiagnosis correlates with dynamometric parameters (muscle strength) and slight amelioration of the motor deficit. Given the small sample size as a limitation, as well as no standardized therapeutic protocol, it should be noted that the 9 patients were the only ones who either attended more than one interval or did more procedures as frequency in time (more often meaning 3 times weekly for 6 months, in 6 patients). Although the most frequent procedures were neuromuscular electrical stimulation (NMES) and proprioceptive neuromuscular facilitation (PNF), the results suggest that regardless of the techniques, the more active patients had better results. Proving the need for long-term rehabilitation, even contrary to the less visible results, can be the trigger point for future research and therapy strategies, as the results suggest central mechanisms involved, adding the cortical ongoing plasticity into the equation.

Limb dominance does not have a meaningful impact on arterial occlusion pressure.

Limb dominancy has been suggested, by some, to influence arterial occlusion pressure (AOP). However, we hypothesized that the differences in AOP between the dominant and nondominant legs were more likely explained by differences in cuff position. To determine the impact of limb dominance, composition, and cuff position on AOP in the context of error associated with measuring AOP twice on the same leg. Fifty-eight adults (30 males) volunteered to have AOP measured on their dominant legs with the cuff bladder covering their inner thighs and on their nondominant legs with the bladder covering their inner and outer thighs (in random order). Thigh circumference and muscle and fat thicknesses were also measured on each leg. We found evidence for differences in AOP between legs [median δ of -0.222, 95% credible interval: (-0.429, -0.016)] when the cuff position was matched. The mean difference was -2.8 mmHg, and the 95% limit of agreement in a Bland-Altman plot was -24.8 to 19.0 mmHg. When plotting this alongside an error range (i.e., 95% limits of agreement) of taking the same measurement twice from our previous study (Spitz et al., 2020), 52 out of 58 measurements were within the error range. This difference was not due to the cuff position. Additionally, there was no evidence that thigh circumference or composition (muscle/fat thickness) moderated any difference between limbs. The difference in AOP between limbs is small and is mostly indistinguishable from the difference observed from taking the measurement twice on the same limb.

Kinematic, Neuromuscular and Bicep Femoris In Vivo Mechanics during the Nordic Hamstring Exercise and Variations of the Nordic Hamstring Exercise

The Nordic hamstring exercise (NHE) is effective at decreasing hamstring strain injury risk. Limited information is available on the in vivo mechanics of the bicep femoris long head (BFLH) during the NHE. Therefore, the purpose of this study was to observe kinematic, neuromuscular and in-vivo mechanics of the BFLH during the NHE. Thirteen participants (24.7 ± 3.7 years, 79.56 ± 7.89 kg, 177.40 ± 12.54 cm) performed three repetitions of the NHE at three horizontal planes (0°, 20° and −20°). Dynamic ultrasound of the dominant limb BFLH, surface electromyography (sEMG) of the contralateral hamstrings and sagittal plane motion data were simultaneously collected. Repeated measures analysis of variance with Bonferroni post hoc corrections were used on the in vivo mechanics and the kinematic and sEMG changes in performance of the NHE. Likely differences in ultrasound waveforms for the BFLH were determined. Significant and meaningful differences in kinematics and in vivo mechanics between NHE variations were observed. Non-significant differences were observed in sEMG measures between variations. Changes to the NHE performance angle manipulates the lever arm, increasing or decreasing the amount of force required by the hamstrings at any given muscle length, potentially changing the adaptive response when training at different planes and providing logical progressions ore regressions of the NHE. All NHE variations result in a similar magnitude of fascicle lengthening, which may indicate similar positive adaptations from the utilization of any variation.

Descending motor drive does not interact with muscle metaboreflex for ventilation regulation during rhythmic exercise in healthy humans.

The muscle metaboreflex effect on pulmonary ventilation (V̇E) regulation is more apparent during rhythmic exercise than rest, possibly because this reflex interacts with other mechanisms regulating V̇E during voluntary contractions, such as central command. Therefore, we tested whether one part of central command, the descending component of motor execution (i.e., descending motor drive), and the muscle metaboreflex interact synergistically to regulate V̇E. Thirteen healthy adults (9 men) completed four experiments in random order under isocapnia. The muscle metaboreflex was activated by rhythmic handgrip exercise at 60% maximal voluntary contraction (MVC) force with the dominant hand. Then, the muscle metaboreflex remained active during a 4-minute recovery period via post-exercise circulatory occlusion (PECO), or it was inactivated, maintaining free blood flow to the dominant upper limb. During the last 2-minutes of the handgrip exercise recovery, participants either performed rhythmic voluntary plantar flexion with the dominant leg at 30% MVC torque to generate descending motor drive or the dominant leg's calf muscles were involuntarily activated by electrical stimulation at a similar torque level (i.e., without descending motor drive). V̇E increased to a similar level during handgrip exercise in all conditions (≈22 L/min, P = 0.364). PECO maintained V̇E elevated above recovery with free blood flow (≈17 L/min vs. ≈13 L/min, P = 0.009). However, voluntary and involuntary plantar flexion with or without PECO evoked similar V̇E responses (∆ ≈ 4 L/min, P = 0.311). Therefore, an interaction between descending motor drive and muscle metaboreflex is not ubiquitous for V̇E regulation during rhythmic exercise.

Comparison of Muscular Activity During Running with New and Used Military Boots and Running Footwears in Healthy Individuals: A Clinical Trial Study

Background: The type of footwear worn by military personnel and others could increase the risk of overuse injuries. Objectives: This study aimed to compare muscular activity during running with new and used military boots and running footwear in healthy individuals. Methods: Thirty healthy males were given a new pair of running footwear (n = 15) and thermoplastic polyurethane military boots (n = 15). Participants in each group were asked to wear these shoes for 6 months. Electromyographic activity of the dominant limb muscles was recorded during running at a speed of 3.3 m/s before and after 6 months. Results: The results indicated significant differences in muscle activity based on the type of footwear worn during various phases of running. Specifically, muscles such as the tibialis anterior, vastus lateralis, rectus femoris, biceps femoris, and semitendinosus showed varied activity during phases such as loading, mid-stance, and push-off. Additionally, there were significant effects of time on certain muscles, including the tibialis anterior and gastrocnemius medialis during the push-off phase. Interactions between footwear type and time were observed for the semitendinosus and gluteus medius during the loading phase, and the gastrocnemius medialis during the push-off phase. Conclusions: The results of this study indicate a decrease in muscle activity for most lower limb muscles in the military boots group compared to the running footwear group during the stance phase of running. The magnitude of gastrocnemius medialis activity increased in the military boots group (but not in the running footwear group) from pre-test to post-test during the push-off phase.