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

Effects of Blood-Flow Restricted Resistance Exercise Versus Neuromuscular Exercise on Mechanical Muscle Function in Adults With Chronic Knee Osteoarthritis-A Secondary Analysis From a Randomized Controlled Trial

Knee osteoarthritis (knee OA) is a prevalent condition worldwide. Globally recognized rehabilitation guidelines for knee OA include patient education and neuromuscular exercises (NEMEX). While heavy-load resistance exercise (70%-90% 1RM) often induces pain with knee OA, low-load exercise (20%-40% 1RM) combined with partial blood-flow restriction (BFR-RE) has been introduced without inducing excessive knee joint pain. The present study aimed to compare the effects of NEMEX and BFR-RE on mechanical muscle function in knee OA individuals. Ninety-six participants (age 56.7 ± 7.6; 47 males, 49 females) with symptomatic, radiographic knee OA were randomized to free-flow land-based NEMEX or unilateral machine-based BFR-RE. Both groups exercised biweekly for 12 weeks while also receiving patient education. Outcomes measured from baseline to 12 weeks included maximal isometric knee extensor strength (MVIC), rate of force development (RFD), maximal leg extensor power (LEP), and cross-sectional area (mCSA) of rectus femoris (RF) and vastus lateralis (VL). Significant (p < 0.01) within-group improvements from baseline to 12 weeks were observed in both groups for MVIC (BFR-RE: +0.4 vs. NEMEX: +0.1 Nm/kg), LEP (+0.6 vs. +0.2 W/kg), mCSA for RF (+1.8 vs. +0.6 cm2), and VL (+3.7 vs. +1.0 cm2). BFR-RE led to increases in RFD (+2.11 (50-ms), +4.48 (200-ms) Nm/s/kg) (p < 0.01), whereas NEMEX did not (p > 0.05). Between-group comparisons revealed greater improvements with BFR-RE for all outcomes (p < 0.01). BFR-RE appears superior to NEMEX in enhancing mechanical muscle function and knee extensor mCSA in knee OA individuals. The enhanced physiological responses observed with BFR-RE suggest that this exercise modality should be considered as an adjunct therapeutic tool in future treatment protocols for knee OA patients.

Inter-Session Reliability of Functional Performance and Muscle Power in Adults With Severe Obesity

Reliable and sensitive testing of physical function is crucial for assessing the effects of treatment or exercise intervention in various patient populations. The present study investigated the test-retest reliability and sensitivity (smallest detectable difference: SDD) of selected physical performance tests commonly used in clinical rehabilitation, including tests of habitual and maximal walking speed, walking endurance capacity, handgrip strength (HGS), and lower limb muscle power (Sit-to-Stand (STS), stair climb) in adults with severe obesity meeting the criteria for bariatric surgery. Thirty-two adults (BMI 43.8 ± 6.6 kg/m2) were enrolled in the study. Participants were assessed in three separate test sessions performed at the same time of day (±2 h) separated by 3 to 7 days. Habitual and maximal walking speed, walking endurance capacity, lower limb muscle power evaluated by stair climb and STS performance, and HGS demonstrated good-to-excellent inter-session reproducibility (ICC: 0.84-0.98, CV and SEM: 2.9%-11.3%) with individual sensitivity (SDD) ranging from 11.8% to 31.2%. Systematic learning effects from test session 1-2 were observed for the STS test and the 3- and 10-m habitual walk speed tests, manifested by increases of 6%-9%, 7%, and 3%, respectively (p < 0.05). Performing a familiarization session (test 1) fully prevented these learning effects (test 2 vs. 3). A majority of physical function tests showed improved reproducibility and sensitivity after the familiarization session. In conclusion, physical function can be assessed in a reliable manner in adults with severe obesity. Further, familiarization sessions prior to actual testing result in improved test-retest reliability and increased sensitivity.

30-sit-to-stand power is a better tool than isometric knee extensor strength to detect motor impairment in people with haemophilic arthropathy

INTRODUCTION

Regular assessment of motor impairments is crucial in people with haemophilic arthropathy (PwHA). This study aimed to determine if there are differences in 30-seconds sit-to-stand (30-STS) power and maximal voluntary isometric contraction (MVIC) of the knee extensors between PwHA and healthy control group (CG). The secondary aims were to investigate the correlation between 30-STS power and MVIC of knee extensors with clinical characteristics and to assess their effectiveness in identifying motor impairment in PwHA.

METHODS

A cross-sectional study was conducted by collecting data from PwHA (n = 17) and a sedentary CG (n = 15). MVIC (torque) and 30-STS power were normalised to body mass. Correlation analysis and simple linear regression adjusted for age were used to assess the association between tests and clinical variables. Using z-scores derived from the mean and standard deviation of the CG, we compared the MVIC and the 30-STS power in PwHA.

RESULTS

PwHA showed lower MVIC and 30-STS power compared to CG (p < .001; large effect size d > .8). Lower 30-STS power was associated with greater joint impairment and greater fear of movement, whereas MVIC showed no association with clinical variables. 30-STS power showed a lower z-score compared to MVIC (p < .001). In addition, 30-STS power detected 47% of PwHA with motor impairment compared to 0% for MVIC (p = .002).

CONCLUSIONS

Our results suggest that 30-STS power may be more effective than knee extensors MVIC in detecting motor impairment in PwHA. Consequently, lower limb skeletal muscle power, rather than maximum knee extensor strength, appears to be more affected in PwHA.

Biomechanics of the lower limb in patients with mild knee osteoarthritis during the sit-to-stand task

BACKGROUND

Knee osteoarthritis (KOA) is a prevalent and debilitating condition that markedly affects the sit-to-stand (STS) activity of patients, a prerequisite for daily activities. Biomechanical recognition of movements in patients with mild KOA is currently attracting attention. However, limited studies have been conducted solely on the observed differences in sagittal plane movement and muscle activation.

AIM

This study aimed to identify three-dimensional biomechanical and muscle activation characteristics of the STS activity in patients with mild KOA.

METHODS

A cross-sectional study was conducted to observe the differences between patients with mild KOA and a control group (CG). It was conducted to observe the differences in muscle activation, including root mean square (RMS%) and integrated electromyography (items), kinematic parameters like range of motion (ROM) and maximum angular velocity, as well as dynamic parameters such as joint moment and vertical ground reaction force (vGRF).

RESULTS

Patients with mild KOA had a higher body mass index and longer task duration. In the sagittal plane, patients with KOA showed an increased ROM of the pelvic region, reduced ROM of the hip-knee-ankle joint, and diminished maximum angular velocity of the knee-ankle joint. Furthermore, patients with KOA displayed increased knee-ankle joint ROM in the coronal plane and decreased ankle joint ROM in the horizontal plane. Integrated vGRF was higher in both lower limbs, whereas the vGRF of the affected side was lower. Furthermore, patients showed a decreased peak adduction moment (PADM) and increased peak external rotation moment in the knee joint and smaller PADM and peak internal rotation moment in the ankle joint. The affected side exhibited decreased RMS% and iEMG values of the gluteus medius, vastus medialis, and vastus lateralis muscles, as well as a decreased RMS% of the rectus femoris muscle. Conversely, RMS% and iEMG values of the biceps femoris, lateral gastrocnemius, and medial gastrocnemius muscles were higher.

CONCLUSION

The unbalanced activation characteristics of the anterior and posterior muscle groups, combined with changes in joint moment in the three-dimensional plane of the affected joint, may pose a potential risk of injury to the irritated articular cartilage.