The contribution of leg press and knee extension strength and power to physical function in people with knee osteoarthritis: A cross-sectional study

Sit-to-stand power predicts functional performance and patient-reported outcomes in patients with advanced knee osteoarthritis. A cross-sectional study

BACKGROUND

Lower limb muscle power is positively associated with functional performance and patient-reported outcomes (PROMs) and suggested as an important variable to evaluate in patients with advanced knee osteoarthritis (OA).

OBJECTIVES

To explore the association between muscle power derived from the 30-sec sit-to-stand test (STS power) with functional performance and PROMs compared to maximal isometric knee extensor strength (KE MVC) in male- and female patients with advanced OA.

STUDY DESIGN

Cross-sectional design.

METHODS

Eighty-six patients (66.6 [64.9-67.7]years) with advanced knee OA were included. Dependent variables were STS power and KE MVC. Independent variables were Timed Up&Go (TUG), 40-m fast-paced walk test (40mFWT), Knee injury and Osteoarthritis Outcome Score (KOOS) subscales.

COVARIATE

Age.

ANALYSES

Simple linear- and multiple regression analyses with and without adjusting for age. Pitman's test was used to evaluate differences in correlation strength among dependent variables.

RESULTS

STS power demonstrated a statistical relationship with TUG and 40mFWT for both sexes (β coefficients -1.11 to -4.36 (p < 0.05), r2 = 0.47-0.55 (p < 0.05)), and with KOOS Pain, ADL, and Sport for male patients (β coefficients 6.53 to 7.17 (p < 0.05), r2 = 0.29-0.33 (p < 0.05)). Knee extensor MVC demonstrated no relationship with any outcomes for male patients or female patients. STS power displayed statistically stronger correlation to functional performance.

CONCLUSION

STS power was associated with functional performance in both male patients and female patients suffering from advanced knee OA. Moreover, STS power was associated with KOOS Pain, Sport, and ADLin male patients. The assessment of STS power should be considered in the evaluation of patients with advanced knee OA.

TRIAL REGISTRATION NUMBER

NCT04081493.

Do people with musculoskeletal pain differ from healthy cohorts in terms of global measures of strength? A systematic review and meta-analysis

OBJECTIVE

It is currently unknown if people with musculoskeletal pain display different multi-joint strength capacities than healthy cohorts. The aim was to investigate whether people with musculoskeletal pain show differences in global measures of strength in comparison to healthy cohorts.

DATA SOURCES

A systematic review was conducted using three databases (Medline, CINAHL and SPORTDiscus) and Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

REVIEW METHODS

Studies involving participants with painful musculoskeletal conditions and multi-joint strength assessment measured at baseline were included. A meta-analysis was also performed to compute standardized mean differences (± 95% confidence intervals), using Hedge's g, and examined the differences in multi-joint strength at baseline between participants with painful musculoskeletal conditions and healthy participants.

RESULTS

In total, 5043 articles were identified, of which 20 articles met the inclusion criteria and were included in the qualitative analysis. The available evidence revealed that multi-joint strength values were limited to knee osteoarthritis, fibromyalgia, chronic low back pain, and rheumatoid arthritis. Only four studies were included in the quantitative synthesis and revealed that only small differences in both chest press (g = -0.34, 95% CI [-0.64, -0.03]) and leg press (g = -0.25, 95% CI [-0.49, -0.02]) existed between adult women with fibromyalgia and active community women.

CONCLUSION

There is a paucity of multi-joint strength values in participants with musculoskeletal pain. Quantitative comparison with healthy cohorts was limited, except for those with fibromyalgia. Adult women with fibromyalgia displayed reduced multi-joint strength values in comparison to active community women.

The relationship between muscle power, functional performance, accelerometer-based measurement of physical activity and patient-reported outcomes in patients with hip osteoarthritis: A cross-sectional study

BACKGROUND

Patients with unilateral hip osteoarthritis appear to have between-leg differences in leg extension power (LEP). The Nottingham Leg Extensor Power Rig provides reliable and valid results but requires sensitive equipment. It would be relevant to identify measures closely associated with this test.

OBJECTIVE

(i) To investigate if LEP is lower in the affected leg compared to the non-affected leg. Furthermore, to investigate the associations between LEP and the measures: (ii) Functional performance, (iii) accelerometer-based measurement of physical activity and (iv) patient-reported outcome measures (PROM).

DESIGN

Cross-sectional study including 60 patients (30 men, 30 women) with hip osteoarthritis scheduled for hip replacement.

METHOD

The counter movement jump and 10-m sprint tests were used to determine functional performance, accelerometer-sensors were used to determine physical activity and the Copenhagen Hip and Groin Outcome Score (HAGOS) was used to determine PROM.

RESULTS

(i) LEP in the affected leg corresponded to 79% [95% CI 74%; 85%] of the non-affected leg, (ii) LEP was positively associated with functional performance tests (β 0.63 to 0.78, p < 0.05), (iii) positively associated although non-significantly with physical activity (β 0.16 to 0.23, p > 0.05) and (iv) positively associated with the six HAGOS subscales (β 0.25 to 0.54, p < 0.05).

CONCLUSION

Functional performance tests may be used as feasible, inexpensive and fast ways to assess LEP in clinical settings. These results may suggest that interventions aimed at improving LEP can improve functional performance and PROM, but not physical activity. Future research is needed to confirm the causality of these cross-sectional findings.

THE CLINICAL TRIAL REGISTRATION NUMBERS

Danish Data Protection Agency (1-16-02-640-14), ClinicalTrials.gov (NTC02301182) and approved by the Danish Biomedical Research Ethics Committee (1-10-72- 343-14) prior to data collection.

Should We Use Unilateral or Bilateral Tasks to Assess Maximal and Explosive Knee Extensor Strength in Patients with Knee Osteoarthritis? A Cross-Sectional Study

Deficits in maximal and explosive knee extensor strength, which are usually assessed with unilateral tasks, are substantial in patients with knee osteoarthritis (KOA). The aim of this study was to investigate the clinical relevance of unilateral vs. bilateral tasks for assessing knee extensor strength in patients with KOA. This was achieved primarily by comparing unilateral and bilateral inter-limb strength asymmetries and secondarily by examining the relationship between unilaterally and bilaterally measured strength, and performance-based and self-reported function. Twenty-four patients with unilateral KOA (mean age: 65 ± 7 years) performed isometric gradual and explosive maximal voluntary contractions to assess, respectively their maximal and explosive strength. Performance-based and self-reported function were also evaluated with standard functional tests and questionnaires, respectively. Inter-limb asymmetries of maximal and explosive strength did not differ significantly between unilateral (mean asymmetry: 26 ± 15%) and bilateral tasks (22 ± 21%). In the same way, the relationships between knee extensor strength-measured either unilaterally or bilaterally-and performance-based or self-reported function were not influenced by the type of task. In conclusion, it does not seem to make a difference in terms of clinical relevance whether maximal and explosive knee extensor strength are evaluated with unilateral or bilateral tasks in KOA patients.

Reduced knee extensor torque production at low to moderate velocities in postmenopausal women with knee osteoarthritis

This study aimed to determine deficits in knee extensor muscle function through the torque-time and torque-velocity relationships and whether these deficits are associated with reduced functional performance in postmenopausal women with knee osteoarthritis (KOA). A clinical sample of postmenopausal women with established KOA (n = 18, ≥55 years) was compared to an age-matched healthy control sample (CON) (n = 26). The deficits in different parameters of the knee extensor torque-time (maximal isometric torque and rate of torque development) and torque-velocity relationship (maximum muscle power, maximal velocity and torque at 0-500°·s^-1 ) were assessed through a protocol consisting of isometric, isotonic and isokinetic tests. Functional performance was evaluated with sit-to-stand and stair-climbing tasks using a sensor-based technology (ie, time- and power-based outcomes). Postmenopausal women with KOA showed reduced maximal isometric torque (Hedge's g effect size (g) = 1.05, p = 0.001) and rate of torque development (g = 0.77-1.17, all p ≤ 0.02), combined with impaired torque production at slow to moderate velocities (g = 0.92-1.70, p ≤ 0.004), but not at high or maximal velocities (g = 0.16, p > 0.05). KOA were slower (g = 0.81-0.92, p ≤ 0.011) and less powerful (g = 1.11-1.29, p ≤ 0.001) during functional tasks. Additionally, knee extensor deficits were moderately associated with power deficits in stair climbing (r = 0.492-0.659). To conclude, knee extensor muscle weakness was presented in postmenopausal women with KOA, not only as limited maximal and rapid torque development during isometric contractions, but also dynamically at low to moderate velocities. These deficits were related to impaired functional performance. The assessment of knee extensor muscle weakness through the torque-time and torque-velocity relationships might enable individual targets for tailored exercise interventions in KOA.

Muscle Function Tests as Supportive Outcome Measures for Performance-Based and Self-Reported Physical Function in Patients With Knee Osteoarthritis: Exploratory Analysis of Baseline Data From a Randomized Trial

Holm, PM, Kemnitz, J, Bandholm, T, Wernbom, M, Schrøder, HM, and Skou, ST. Muscle function tests as supportive outcome measures for performance-based and self-reported physical function in patients with knee osteoarthritis: Exploratory analysis of baseline data from a randomized trial. J Strength Cond Res XX(X): 000-000, 2020-Uncertainty on the role of muscle function in relation to physical function in knee osteoarthritis (KOA) persists. This study aimed to assess the associations between muscle function and performance-based and self-reported physical function in patients with KOA. Physical function in 80 subjects with symptomatic and radiographic KOA was assessed using 40-m fast-paced walk, 30-second chair stand, 9-step stair climb tests, and the subscale activities of daily living from the Knee injury and Osteoarthritis Outcome Score (KOOS-ADL). Measurements of muscle function included leg extension (LE) power, knee extension (KE) torque, and estimated leg press one repetition maximum (LP RM). Associations were investigated using multivariable hierarchical linear regressions adjusted for age, sex, body mass index, self-reported physical activity, and thigh muscle lean area. Leg extension power was significantly associated with 40-m walk, stair climb, and 30-second chair stand, explaining 18, 8, and 3% of additional variance, respectively. Knee extension torque explained 13, 7, 17, and 7% of additional variance in the 40-m walk, stair climb, 30-second chair stand, and KOOS-ADL, respectively. Leg press one repetition maximum explained 11% of additional variance in the 30-second chair stand. In conclusion, LE power was the best explanatory variable for performance on the 40-m walk and stair climb tests, whereas KE torque best explained chair stand performance. Only KE torque was associated with KOOS-ADL. Our results highlight the importance of selecting supportive muscle function tests based on the specific physical function and suggest that other factors may be more important for certain physical function outcomes. Level of significance p < 0.05. Trial identifier: NCT03215602.

Low-dose strength training in addition to neuromuscular exercise and education in patients with knee osteoarthritis in secondary care - a randomized controlled trial

OBJECTIVES

To investigate the effects of lower limb strength training in addition to neuromuscular exercise and education (ST + NEMEX-EDU) compared to neuromuscular exercise and education alone (NEMEX-EDU) on self-reported physical function in patients with knee osteoarthritis (KOA).

DESIGN

Patient-blinded, parallel-group randomized controlled trial (RCT).

METHODS

The trial included 90 patients in secondary care with radiographic and symptomatic KOA, ineligible for knee replacement. Both groups exercised twice weekly for 12 weeks. Additional strength training consisted of a single, fatiguing knee extension set (30-60RM) before four sets of leg-press (8-12RM). Primary outcome was the between-group difference on the subscale activities of daily living from the Knee Injury and Osteoarthritis Outcome Score (KOOS_ADL) at 12 weeks. Secondary outcomes included KOOS symptoms, pain, function in sport and recreation, and quality of life, 40 m walk, stair climb, leg extension power, EuroQol-5D-5L, pain medication usage, and adverse events.

RESULTS

There was no statistically significant between-group difference in KOOS_ADL at 12-weeks; adjusted mean difference -1.15 (-6.78 to 4.48). Except for the stair climb test, which demonstrated an adjusted mean difference of 1.15 (0.09-2.21) in favor of ST + NEMEX-EDU, all other outcomes showed no statistically significant between-group differences. Neither group improved leg extension power.

CONCLUSION

The addition of lower-limb strength training, using a low-dose approach, to neuromuscular exercise and education carried no additional benefits on self-reported physical function or on most secondary outcomes. Both groups displayed similar improvements at 12-week follow-up. Hence, the current low-dose strength training approach provided no additional clinical value in this group of KOA patients. Trial identifier (ClinicalTrials.gov): NCT03215602.

Eccentric and Concentric Resistance Exercise Comparison for Knee Osteoarthritis

INTRODUCTION

This study aimed to compare the efficacy of eccentrically focused resistance exercise (ECC RT) to concentrically focused resistance exercise (CNC RT) on knee osteoarthritis (OA) symptoms and strength.

METHODS

Ninety participants consented. Participants were randomized to CNC RT, ECC RT, or a wait-list, no-exercise control group. Four months of supervised exercise training was completed using traditional weight machines (CNC RT) or modified-matched machines that overloaded the eccentric action (ECC RT). Main outcomes included one-repetition maximal strength (knee extension, leg flexion, and leg press), weekly rate of strength gain, Western Ontario and McMaster University Osteoarthritis Index (WOMAC) total score and subscores.

RESULTS

Fifty-four participants (60-85 yr, 61% women) completed the study. Both CNC RT and ECC RT groups showed 16%-28% improvement relative to the wait-list, no-exercise control group (P = 0.003-0.005) for all leg strength measures. The rate of weekly strength gain was greater for CNC RT than for ECC RT for leg press and knee flexion (by 2.9%-4.8%; both, P < 0.05) but not knee extension (0.7%; P = 0.38). There were no significant differences in WOMAC total and subscores across groups over time. Leg press strength change was the greatest contributor to change in WOMAC total scores (R = 0.223). The change in knee flexion strength from baseline to month 4 was a significant predictor of the change in WOMAC pain subscore (F ratio = 4.84, df = 45, P = 0.032). Both modes of strength training were well tolerated.

CONCLUSIONS

Both resistance training types effectively increased leg strength. Knee flexion and knee extension muscle strength can modify function and pain symptoms irrespective of muscle contraction type. Which mode to pick could be determined by preference, goals, tolerance to the contraction type, and equipment availability.

Level of pain, muscle strength and posture: effects of PBM on an exercise program in women with knee osteoarthritis - a randomized controlled trial

To evaluate the effectiveness of an exercise program associated to photobiomodulation (PBM) on pain, postural changes, functionally, and muscular strength in women, one of the risk factors, with knee osteoarthritis (OA). A randomized controlled trial, with a blinded assessor and intention-to-treat analysis and placebo control. Sixty-two participants with knee OA (with confirmed radiological diagnosis) were evaluated for this study. However, 34 were considered eligible and were randomized into two groups: EPPG - exercise and PBM placebo group (n = 17) and EPAG - exercise and PBM active group (n = 16), but one participant was excluded of EPAG. The exercise program and PBM (808 nm, 100 mW/point, 4 J/point, 56 J total, 91 J/cm²) were realized twice a week, during 8 weeks. West Ontario and the McMaster University Osteoarthritis Index (WOMAC) and Lequesne questionnaires, 1-repetition maximum test (1-RM) and posture evaluation software (SAPO) were used to analyze the effects of the therapies. In intragroup analysis, a significant improvement in pain WOMAC (p < 0.001), stiffness (p < 0.001), function (p < 0.001), Lequesne (p < 0.001), and 1-RM (all muscle groups) (p < 0.001) were observed. In this study, the exercise program improved pain, function, and muscle strength of all the participants. However, PBM, in the parameters used, did not optimize the effects of the exercise program in women with knee OA.

Jumping Joints: The Complex Relationship Between Osteoarthritis and Jumping Mechanography

We investigated the relationship between lower limb osteoarthritis (OA) and muscle strength and power (assessed by jumping mechanography) in UK community-dwelling older adults. We recruited 249 older adults (144 males, 105 females). OA was assessed clinically at the knee according to ACR criteria and radiographically, at the knee and hip, using Kellgren and Lawrence grading. Two-footed jumping tests were performed using a Leonardo Mechanography Ground Reaction Force Platform to assess maximum muscle force, power and Esslinger Fitness Index. Linear regression was used to assess the relationship between OA and jumping outcomes. Results are presented as β (95% confidence interval). The mean age of participants was 75.2 years (SD 2.6). Males had a significantly higher maximum relative power during lift off (mean 25.7 W/kg vs. 19.9 W/kg) and maximum total force during lift off (mean 21.0 N/kg vs. 19.1 N/kg) than females. In adjusted models, we found significant associations in males between clinical knee OA and maximum relative power [- 6.00 (CI - 9.10, - 2.94)] and Esslinger Fitness Index [- 19.3 (- 29.0, - 9.7)]. In females, radiographic knee OA was associated with total maximum power [- 2.0 (- 3.9, - 0.1)] and Esslinger Fitness Index [- 8.2 (- 15.9, - 0.4)]. No significant associations were observed for maximum total force. We observed significant negative associations between maximum relative power and Esslinger Fitness Index and clinical knee OA in males and radiographic knee OA in females. We have used novel methodology to demonstrate relationships between muscle function and OA in older adults.

Photobiomodulation via a cluster device associated with a physical exercise program in the level of pain and muscle strength in middle-aged and older women with knee osteoarthritis: a randomized placebo-controlled trial

Osteoarthritis (OA) is a chronic joint disease that leads to pain and functional incapacity. The aim of the study is to investigate the effects of the incorporation of photobiomodulation (PBM) (via cluster) into a physical exercise program on the level of pain, lower limb muscle strength, and physical capacity, in patients with knee OA. Sixty-two female volunteers with a diagnosis of knee OA were distributed in 4 groups: exercise associated with placebo PBM group, exercise associated with active PBM group, active PBM group, and placebo PBM group. Sixteen sessions of lower limb strength exercises and PBM via cluster (808 nm, 100 mW, 7 points each side, 56 J total) were performed. The level of pain, physical capacity, and lower limb muscle strength were evaluated with the use of the numeric pain rating scale (NPRS), 6-min walking test (6-MWT) and timed up and go (TUG), and maximal voluntary isometric torque (MVIT) before and after the interventions. Both groups presented a significant decrease in the level of pain when compared with the placebo-treated women. Furthermore, the 6-MWT showed that the trained groups (with or without PBM) demonstrated higher values in the distance walked comparing pre and post-treatment values. The same behavior was found for the MVIT load before and after intervention. TUG was higher for all the treated with exercise groups comparing the pre and post-treatment values. Physical exercise and PBM showed analgesic effects. However, PBM did not have any extra effect along with the effects of exercise in improving the distance walked, the TUG, and the muscle strength.Trial registration: RBR-7t6nzr.

Relationship Between Strength Parameters and Functional Performance Tests in Patients With Severe Knee Osteoarthritis

BACKGROUND

Decreased leg muscle strength is a major determinant of reduced function in patients with knee osteoarthritis (OA). The identification of a strength parameter that is best correlated with functional performance is important for monitoring rehabilitation results.

OBJECTIVE

To determine which muscle strength measurements show the highest correlation with functional capacity in patients with severe knee OA shortly before total knee arthroplasty (TKA).

DESIGN

Cross-sectional exploratory study.

SETTING

Outpatient rehabilitation department at a university teaching hospital.

PATIENTS

The sample included 75 patients (51 female) scheduled for primary TKA, recruited through multistage sampling.

METHODS OR INTERVENTIONS

Independent variables were peak isometric, isokinetic concentric, and eccentric leg extensor strength measured on the leg press, as well as peak isometric knee extensor strength measured on the strength chair. Two multiple regression analyses were performed, one including all strength measures and the other including all of the strength ratios. Pearson correlation coefficients were calculated between the strength measures and functional test scores.

MAIN OUTCOME MEASUREMENTS

Dependent variables were the Timed Up and Go Test (TUG) and the Stair Test (ST).

RESULTS

The regression analysis including all strength measures could explain 11.9% of the variance of the TUG (P = .068, not significant [NS]) and 21.5% of the variance of the ST (P = .009, significant). The regression model for the strength ratios explained 11.8% of the variance of the TUG (P = .090, NS) and 6.3% of the ST (P = .217, NS).

CONCLUSIONS

Although univariate analysis confirmed significant correlations between strength measurements and functional tests, multiple regression analysis revealed a higher predictive value for the ST than for the TUG. The use of both muscle strength tests and performance-based function tests is advisable to evaluate functional impairments of patients with knee OA.

LEVEL OF EVIDENCE

III.

Acutherapy for Knee Osteoarthritis Relief in the Elderly: A Systematic Review and Meta-Analysis

Purpose

This systematic review and meta-analysis was conducted to investigate the effects of various acutherapies on knee osteoarthritis (KOA) relief in the elderly.

Methods

Five databases were accessed from inception to July 2017 for searching randomized controlled trials (RCTs) on acutherapy for KOA relief in the elderly. Data were pooled after trial quality assessment for meta-analysis. Outcomes were the scores of knee pain, knee stiffness, and physical function accessed by Western Ontario and McMaster Universities Osteoarthritis (WOMAC) Index.

Results

17 RCTs including 4774 subjects were included. The results indicated that acutherapy significantly affected knee pain (standardized mean difference, i.e., SMD = - 0.73, [95% CI, -0.98 to -0.47], P <0.001), knee stiffness (SMD = -0.66, [95%CI, -0.85 to -0.47], P <0.001), and physical function (SMD = -1.56, [95%CI, -2.17 to -0.95], P<0.001) when compared with control condition without intervention of any acutherapy. Moreover, acutherapy was more effective than corresponding sham (placebo) intervention applied on nonacupoints (SMD = -0.16, [95% CI, -0.32 to -0.01], P = 0.04). However, no significant differences were found on treatment effects between acutherapy and sham acutherapy at the same acupoints (SMD= - 0.09, [95%CI, -0.40 to 0.21], P = 0.55).

Conclusions

Acutherapy was an effective approach for KOA relief in the elderly. The selection of acupoints position could be a crucial factor that influences the treatment efficacy of acutherapy.

Quadriceps Rate of Torque Development and Disability in Persons With Tibiofemoral Osteoarthritis

Background Declines in the ability to rapidly generate quadriceps muscle torque may underlie disability in individuals with tibiofemoral osteoarthritis. Objective To determine whether quadriceps rate of torque development (RTD) predicts self-reported disability and physical performance outcomes in individuals with tibiofemoral osteoarthritis. Methods This controlled laboratory, cross-sectional study assessed quadriceps strength and RTD in 76 individuals (55% female; mean ± SD age, 61.83 ± 7.11 years) with symptomatic and radiographic tibiofemoral osteoarthritis. Early (0-50 milliseconds), late (100-200 milliseconds), and overall peak RTDs were quantified in the symptomatic (involved) and contralateral limbs and used to calculate bilateral average values. Disability was assessed using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) function subscale and 3 physical performance tests, including the (1) 20-m fast-paced walk, (2) 30-second chair stand, and (3) timed stair climb. Separate univariate regression models were used to determine the unique associations among measures of quadriceps RTD, WOMAC function score, and physical performance outcomes after accounting for quadriceps strength (change in R²). Results Greater involved-side late RTD and greater bilateral average early RTD were associated with faster walking (change in R² = 0.05, P = .013 and change in R² = 0.05, P = .043, respectively). Greater bilateral average late RTD was associated with faster walking (change in R² = 0.20, P<.001) and faster stair climb (change in R² = 0.11, P = .001). No quadriceps RTD variable was significantly associated with WOMAC function score (change in R² range, <0.01-0.017). Conclusion Involved-limb quadriceps RTD was weakly associated with physical performance outcomes, but not self-reported disability, in individuals with tibiofemoral osteoarthritis. Bilateral average quadriceps RTD was moderately associated with walking speed. Level of Evidence Prognosis, level 2b. J Orthop Sports Phys Ther 2018;48(9):694-703. Epub 22 May 2018. doi:10.2519/jospt.2018.7898.