Quadriceps strength training is a key component of pulmonary rehabilitation (PR). Clinical interpretability of changes in muscle strength following PR is however limited due to the lack of cut-off ...values to define clinical improvement. This study estimated the minimal clinically important difference (MCID) for the isotonic and isometric quadriceps muscle strength assessed with the one-repetition maximum (1RM) and hand-held dynamometry (HHD) in people with chronic obstructive pulmonary disease (COPD) following PR.
A secondary analysis of a real life non-randomised controlled study was conducted in people with COPD enrolled in a 12-week community-based PR programme. Anchor and distribution-based methods were used to compute the MCIDs. The anchors explored were the St. George's respiratory questionnaire (SGRQ) and the six-minute walk test (6MWT) using Pearson's correlations. Pooled MCIDs were computed using the arithmetic weighted mean (2/3 anchor, 1/3 distribution-based methods) and reported as absolute and/or percentage of change values.
Eighty-nine people with COPD (84% male, 69.9 ± 7.9 years, FEV
1
49.9 ± 18.9% predicted) were included. No correlations were found between changes in 1RM and the SGRQ neither between changes in HHD and the SGRQ and 6MWT (p > 0.05). Thus, anchor-based methods were used only in the MCID of the 1RM with the 6MWT as the anchor. The pooled MCIDs were 5.7Kg and 26.9% of change for the isotonic quadriceps muscle strength with 1RM and 5.2KgF for isometric quadriceps muscle strength assessed with HHD.
The MCIDs found are estimates to improve interpretability of community-based PR effects on quadriceps muscle strength and may contribute to guide interventions.
The lateral medicine ball throw (LMBT) test is used to evaluate the throwing action, involving the entire kinetic chain and the principle of force transfer, with association between the strength of ...the lower limb and trunk muscles and the lower limb kinematics. The LMBT to investigate the association between lower limb kinematics and hip and trunk muscle strength.
This was a cross-sectional study with 84 healthy and physically active young people. Determinations were made of the maximum isometric strengths of the hip abductor, lateral rotator, extensor, and flexor muscles, and the trunk lateral flexors and extensors. Kinematic analyses (2D) of the hip, knee, and ankle in the sagittal and frontal planes were performed during the countermovement phase of the LMBT, together with quantification of LMBT. Statistical analysis of the associations employed multiple linear regression, with α = 5%.
There were significant associations between the LMBT and the independent variables hip extensors strength, trunk flexors strength, valgus angle, and knee flexion angle and gender. The regression model presented adjusted R2 = 0.622.
LMBT was influenced by the trunk flexor and hip extensor muscle strengths, knee flexion kinematics, lower limb valgus in the countermovement phase, and gender.
Background
Idiopathic toe walking (ITW) is an exclusionary diagnosis. There has been limited exploration of lower limb active range of motion and strength measures in children with ITW. This ...researched aimed to determine any differences in lower limb muscle active range of motion and strength in children who have ITW, compared to normative data collected from children who displayed typical gait.
Methods
Children were recruited with had a diagnosis of ITW, aged between 4 and 10 years, and no recent treatment. Data collected included parent reported data such as time spent toe walking, percentage of time spent toe walking, and clinician collected data such as age, height and weight. Joint ranges of motion and strength measures were collected by an experience clinician. Active and weight bearing joint ranges of motion were evaluated with a goniometer or digital inclinometer. Lower limb muscle strength measures were evaluated with a hand‐held dynamometer. Published normative data sets were used for comparison. Measures were analysed with regression analyses to determine differences between groups in different measures, considering measures known to impact range and strength. Odds ratios (OR), 95% confidence intervals (CI) and p values were reported.
Results
Twenty‐six children with ITW participated. Reduced weight bearing ankle range of motion, when measured with the knee bent, was associated with being in the ITW group (p = 0.009), being older (p < 0.001) and weighing less (p < 0.001). Reduced ankle plantar flexion range was only associated with being in the ITW group (p = 0.015). For all lower limb strength measures, excluding hip external rotation, children who displayed greater strength, did not toe walk (p < 0.002), were older (p < 0.001) and weighed more (p < 0.014). with ITW.
Conclusion
Children with ITW displayed reduced overall plantar and dorsiflexion at the ankle, compared to non‐toe walking children. Reduced plantarflexion is children with ITW has not been described before, however reduced dorsiflexion is commonly reported. Children with ITW were weaker in many lower limb measures, even when age and weight were considered. This should lead clinicians and researchers to pay greater attention to lower limb strength measures in this population.
Lower grip strength on admission to hospital is known to be associated with longer stay, but the link between customary grip and risk of future admission is less clear.
To compare grip strength with ...subsequent risk of hospital admission among community-dwelling older people in a U.K. setting.
Cohort study with linked administrative data.
Hertfordshire, U.K.
A total of 2,997 community-dwelling men and women aged 59-73 years at baseline.
The Hertfordshire Cohort Study (HCS) participants completed a baseline assessment between 1998 and 2004, during which grip strength was measured. Hospital Episode Statistics and mortality data to March 2010 were linked with the HCS database. Statistical models were used to investigate the association of grip strength with subsequent elective, emergency and long-stay hospitalisation and readmission.
There was a statistically significant negative association between grip strength and all classes of admission in women unadjusted hazard ratio per standard deviation (SD) decrease in grip strength for: any admission/death 1.10 (95% CI: 1.06, 1.14), elective admission/death 1.09 (95% CI: 1.05, 1.13), emergency admission/death 1.21 (95% CI: 1.13, 1.31), long-stay admission/death 1.22 (95% CI: 1.13, 1.32) and unadjusted relative risk per SD decrease in grip strength for 30-day readmission/death 1.30 (95% CI: 1.19, 1.43). These associations remained significant after adjustment for potential confounding factors (age, height, weight for height, smoking, alcohol, social class). In men, unadjusted rates for emergency admission/death, long-stay admission/death and readmission/death were significantly associated with grip strength; associations that similarly withstood adjustment.
This study provides the first evidence that grip strength among community-dwelling men and women in the U.K. is associated with risk of hospital admission over the following decade.
The hamstring to quadriceps (H : Q) strength ratio is widely used to identify individuals at risk of sustaining hamstring strain injuries. However, its efficacy is not supported by the current ...evidence. Current methods for the calculation of the H : Q ratio provide only a one- or two-dimensional ratio, often ignoring fundamental muscle mechanical properties. Based on isokinetic torque measurements of the knee flexors and extensors (0-400° s
) in 25 young, physically active males, we derived a model equation that creates a three-dimensional H : Q functional ratio profile. The model robustness was tested against a different number of input torque data (8, 11, 14 and 17 pairs of points) and small perturbation of the knee joint angle data (5°). The model was consistent and behaved well under all conditions apart from the eight pairs of points (
= 0.84-0.96; RMSE = 0.14-0.25; NRMSE = 0.12-0.27), and the H : Q functional ratio was successfully described even at angles and velocities that cannot be normally assessed with isokinetic dynamometry. Overall, our results suggest that the model can provide a fast and accurate three-dimensional description of the knee joint muscle strength balance using as few as 11 experimental data points and this could be an easy-to-employ screening tool.
Objective
To investigate the differences in pelvic floor muscle (PFM) morphology and function between female runners with and without running‐induced stress urinary incontinence (RI‐SUI).
Design
This ...was a cross‐sectional, observational study.
Methods
Experienced female runners were recruited into two groups: runners who regularly experience RI‐SUI (n = 19) and runners who do not (n = 20). Active and passive pelvic floor muscle (PFM) properties were assessed using intravaginal dynamometry during maximal voluntary contractions (MVC) and during passive tissue elongation. The morphology of the urethra and PFMs was assessed using 2D and 3D transperineal ultrasound imaging. Independent t tests or Mann–Whitney U were used as appropriate to test group differences on all study outcomes, and Cohen's d effect sizes were calculated.
Results
The rate of force development during the MVC was significantly higher in participants reporting RI‐SUI (p ≤ 0.05) and conversely, significantly lower during passive elongation of the PFMs (p ≤ 0.05) compared to runners with no history of leakage. Concurrently, the extent of bladder neck elevation between rest and maximum voluntary activation was significantly higher among those with RI‐SUI compared to those without. Although not significant, small to moderate effect sizes were observed for other outcomes—active force outcomes measured during MVC tended to be higher in runners with RI‐SUI, while passive force outcomes measured during passive tissue elongation tended to be lower. The cross‐sectional area of the urethral wall and the area of the levator hiatus tended to be larger in runners with RI‐SUI compared to those without.
Conclusion
Runners who experience RI‐SUI demonstrate better PFM contractile function but lower passive support when compared to their continent counterparts.
To determine the concurrent validity, reliability, and minimal detectable change (MDC) of the hand-held dynamometry (HHD) for knee strength measurement in patients with revision total knee ...arthroplasty (r-TKA).
A reliability and validity analysis.
Orthopedic and physical therapy services of university hospital.
The study included 42 patients with r-TKA (N=42).
Not applicable.
Knee muscle strength assessments were performed by 2 physiotherapists in 3 different sessions by using HHD. Participants were instructed to exert a maximal force for lasting 5 seconds against HHD. The first examiner performed the strength testing, and after 30-minutes rest, the second examiner performed the same procedure for inter-examiner reliability. One hour after the initial testing, the first examiner reperformed the strength testing for intra-examiner reliability. The correlations of the knee extensors and knee flexors strength with 50-foot walking test and 30-second chair stand test were assessed for concurrent validity.
The inter-examiner reliabilities of knee extensors and flexors strength measurements were 0.97 and 0.95, respectively. The SEM and the minimal detectable changes at 95% confidence level (MDC
) for knee extensors were 10.39 and 28.65 Newton-meters (Nm), and SEM and MDC
for knee flexors were 8.70 and 23.99 Nm, respectively. The intra-examiner reliabilities of knee extensors and flexors strength measurements were 0.96. SEM and MDC
for knee extensors were 12.00 and 33.09 Nm, and SEM and MDC
for knee flexors were 7.78 and 21.45 Nm, respectively. The knee muscle strength showed strong significant correlations with physical performance tests (all, P<.05).
The HHD is a reliable and valid method for assessment of static knee strength after r-TKA. The HHD can be used to quantify changes in knee strength and also assists the clinicians to determine the effect of rehabilitation programs on muscle strength following r-TKA surgery.
ABSTRACT
Introduction: Hand‐held dynamometry (HHD) is commonly used to measure ankle plantarflexion strength but has variable reliability measuring higher forces. Fixed HHD is suggested to improve ...reliability. We, therefore, compared the reliability, consistency, and accuracy of measuring plantarflexion strength. Methods: Plantarflexion strength was measured in 25 healthy individuals with fixed HHD and HHD alone. Intraclass correlation coefficients (ICC2,2), SEM, minimal detectable change, and Spearman correlation coefficients were calculated to assess inter‐trial repeatability, consistency, agreement, and accuracy. Results: Both methods were repeatable (ICC2,2 0.96 to 0.98) and highly correlated (Spearman rho = 0.815; P < 0.01). Fixed HHD produced significantly higher force outputs. HHD alone provided more consistent force values. Conclusions: Both methods of measuring ankle plantarflexion force were reliable. Force measured with fixed HHD will likely be more accurate for adults and individuals with greater strength, while HHD alone will be more consistent for individuals with lower strength. Muscle Nerve 56: 896–900, 2017
Abstract
We have recently demonstrated that dietary nitrate, a source of nitric oxide (NO) via the nitrate → nitrite → NO enterosalivary pathway, can improve muscle contractility in healthy older men ...and women. Nitrate ingestion has also been shown to reduce blood pressure in some, but not all, studies of older individuals. However, the optimal dose for eliciting these beneficial effects is unknown. A pilot randomized, double-blind, placebo-controlled crossover study was therefore performed to determine the effects of ingesting 3.3 mL/kg of concentrated beetroot juice containing 0, 200, or 400 µmol/kg of nitrate in 9 healthy older subjects (mean age 70 ± 1 years). Maximal knee extensor power (Pmax) and speed (Vmax) were measured ~2.5 hours after nitrate ingestion using isokinetic dynamometry. Blood pressure was monitored periodically throughout each study. Pmax (in W/kg) was higher (p < .05) after the lower dose (3.9 ± 0.4) compared to the placebo (3.7 ± 0.4) or higher dose (3.7 ± 0.4). Vmax (in rad/s) also tended to be higher (p = .08) after the lower dose (11.9 ± 0.7) compared to the placebo (10.8 ± 0.8) or higher dose (11.2 ± 0.8). Eight out of 9 subjects achieved a higher Pmax and Vmax after the lower versus the higher dose. These dose-related changes in muscle contractility generally paralleled changes in breath NO levels. No significant changes were found in systolic, diastolic, or mean arterial blood pressure. A lower dose of nitrate increases muscle speed and power in healthy older individuals, but these improvements are lost at a higher dose. Blood pressure, on the other hand, is not reduced even with a higher dose.
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