Chinese translation and validation of the Oxford Knee Scale for patients with knee osteoarthritis

Background: Oxford Knee Scale (OKS) is a commonly used instrument to assess the symptoms and functional status in people with knee osteoarthritis. However, a Chinese version of this scale is not yet available. Objective: The objective of this study was to translate the OKS into Chinese and validate the Chinese version of OKS. Methods: The Chinese OKS was translated from the original English version following the recommendations of the International Society for Pharmacoeconomics and Outcomes Research. One hundred Chinese reading patients with knee osteoarthritis were recruited from local hospitals and physiotherapy clinics. Psychometric properties were evaluated in terms of test-retest reliability and internal consistency. Convergent validity was examined by Spearman rank correlation coefficient tests by comparing its score with the validated Chinese version of the Western Ontario and McMaster Universities Osteoarthritis Index and Health Outcome Survey Short Form-36. Results: Chinese OKS demonstrated excellent reliability (intraclass correlation coefficient = 0.88). Cronbach a of individual questions was > 0.7. Strong correlation was found between the Chinese OKS and the Western Ontario and McMaster Universities Osteoarthritis Index (r > 0.553, p < 0.001). Fairly strong negative correlation was also found between Chinese OKS and Health Outcome Survey Short Form-36 (p = -0.273 to -0.666, p < 0.05). Conclusion: The Chinese translated version of OKS is a reliable and valid instrument for clinical evaluation in Chinese reading patients with knee osteoarthritis

Do rotational shear-cushioning shoes influence horizontal ground reaction forces and perceived comfort during basketball cutting maneuvers?

Background. Court shoe designs predominantly focus on reducing excessive vertical ground reaction force, but shear force cushioning has received little attention in the basketball population. We aimed to examine the effect of a novel shoe-cushioning design on both resultant horizontal ground reaction forces and comfort perception during two basketball-specific cutting movements. Methods. Fifteen university team basketball players performed lateral shuffling and 45-degree sidestep cutting at maximum effort in basketball shoes with and without the shear-cushioning system (SCS). Paired t-tests were used to examine the differences in kinetics and comfort perception between two shoes. Results. SCS shoe allowed for larger rotational material deformation compared with control shoes, but no significant shoe differences were found in braking phase kinetics during both cutting movements (P = 0.35). Interestingly, a greater horizontal propulsion impulse was found with the SCS during 45-degree cutting (P 0.05). Discussion. The application of a rotational shear-cushioning structure allowed for better forefoot comfort and enhanced propulsion performance in cutting, but did not influence the shear impact. Understanding horizontal ground reaction force information may be useful in designing footwear to prevent shear-related injuries in sport populations

A validation study of a smartphone application for functional mobility assessment of the elderly

Background: To minimize the reaction time and position judgment error using stopwatch-timed measures, we developed a smartphone application to measure performance in the five-time sit-to-stand (FTSTS) and timed up-and-go (TUG) tests. Objective: This study aimed to validate this smartphone application by comparing its measurement with a laboratory-based reference condition. Methods: Thirty-two healthy elderly people were asked to perform the FTSTS and TUG tests in a randomized sequence. During the tests, their performance was concurrently measured by the smartphone application and a force sensor installed in the backrest of a chair. The intraclass correlation coefficient [ICC(2,1)] and Blande-Altman analysis were used to calculate the measurement consistency and agreement, respectively, between these two methods. Results: The smartphone application demonstrated excellent measurement consistency with the lab-based reference condition for the FTSTS test [ICC(2,1) = 0.988] and TUG test [ICC(2,1) = 0.946]. We observed a positive bias of 0.27 seconds (95% limits of agreement, -1.22 to 1.76 seconds) for the FTSTS test and 0.48 seconds (95% limits of agreement, -1.66 to 2.63 seconds) for the TUG test. Conclusion: We cross-validated the newly developed smartphone application with the laboratory-based reference condition during the examination of FTSTS and TUG test performance in healthy elderly

The effect of support surface and footwear condition on postural sway and lower limb muscle action of the older women

Background: Diminished somatosensory function is a critical age-related change which is related to postural instability in the older population. Footwear is a cost-effective way to modulate the postural stability by altering sensorimotor inputs via mechanoreceptors on the plantar surface of the feet. Compared to insoles with indentions in the entire surface, we innovatively developed a textured insole with site-specific nodulous protrudous. This study thus aimed to investigate the immediate effect of the nodulous insole and supporting surface condition on static postural stability and lower limb muscle activation for healthy older women. Methods: This is a single-session study with repeated measurements. Twenty-three healthy older women stood on the firm (i.e., concrete floor) and foam surfaces with their eyes open in the three footwear conditions, namely barefoot, plain shoes and shoes with an innovative textured insole, for 30 seconds. Static postural sway and muscle activation of biceps femoris (BF), vastus lateralis (VL), tibialis anterior (TA), and lateral gastrocnemius (LG) of the dominant leg were measured during each testing condition. Results: Compared to a firm surface, standing on the foam could significantly increase the body sway and lower limb muscle activation (p<0.05). When standing on the foam, compared to barefoot, wearing footwear significantly decreased the VL and TA muscle activation and minimize the postural sway in medial-lateral and anterior-posterior direction, while the influence is larger for the shoes with nodulous insloe compared to the plain shoes. No significant differences between the footwear conditions for static stability and muscle activation were observed on firm surface condition. Conclusions:For older women, footwear could improve the postural stability in the unstable surface, particularly the footwear with nodulous insole, with the underlying mechanism as enhancing the mechanoreceptors on the plantar surface of the feet

Validation and reliability of the Physical Activity Scale for the Elderly in Chinese population

Objectives: Physical Activity Scale for the Elderly (PASE) is a widely used questionnaire in epidemiological studies for assessing the physical activity level of elderly. This study aims to translate and validate PASE in Chinese population. Design: Cross-sectional study. Subjects: Chinese elderly aged 65 or above. Methods: The original English version of PASE was translated into Chinese (PASE-C) following standardized translation procedures. Ninety Chinese elderly aged 65 or above were recruited in the community. Test-retest reliability was determined by comparing the scores obtained from two separate administrations by the intraclass correlation coefficient. Validity was evaluated by Spearman’s rank correlation coefficients between PASE and Medical Outcome Survey 36-Item Short Form Health Survey (SF-36), grip strength, single-leg-stance, 5 times sit-to-stand and 10-m walk. Results: PASE-C demonstrated good test-retest reliability (intraclass correlation coefficient  =0.81). Fair to moderate association were found between PASE-C and most of the subscales of SF-36 (rs=0.285 to 0.578, p<0.01), grip strength (rs=0.405 to 0.426, p<0.001), single-leg-stance (rs =0.470 to 0.548, p<0.001), 5 times sit-to-stand (rs =–0.33, p=0.001) and 10-m walk (rs =–0.281, p=0.007). Conclusion: PASE-C is a reliable and valid instrument for assessing the physical activity level of elderly in Chinese population

Plasticity of muscle synergies through fractionation and merging during development and training of human runners

Complex motor commands for human locomotion are generated through the combination of motor modules representable as muscle synergies. Recent data have argued that muscle synergies are inborn or determined early in life, but development of the neuromusculoskeletal system and acquisition of new skills may demand fine-tuning or reshaping of the early synergies. We seek to understand how locomotor synergies change during development and training by studying the synergies for running in preschoolers and diverse adults from sedentary subjects to elite marathoners, totaling 63 subjects assessed over 100 sessions. During development, synergies are fractionated into units with fewer muscles. As adults train to run, specific synergies coalesce to become merged synergies. Presences of specific synergy-merging patterns correlate with enhanced or reduced running efficiency. Fractionation and merging of muscle synergies may be a mechanism for modifying early motor modules (Nature) to accommodate the changing limb biomechanics and influences from sensorimotor training (Nurture)

Walking with head-mounted virtual and augmented reality devices : effects on position control and gait biomechanics

What was once a science fiction fantasy, virtual reality (VR) technology has evolved and come a long way. Together with augmented reality (AR) technology, these simulations of an alternative environment have been incorporated into rehabilitation treatments. The introduction of head-mounted displays has made VR/AR devices more intuitive and compact, and no longer limited to upper-limb rehabilitation. However, there is still limited evidence supporting the use of VR and AR technology during locomotion, especially regarding the safety and efficacy relating to walking biomechanics. Therefore, the objective of this study is to explore the limitations of such technology through gait analysis. In this study, thirteen participants walked on a treadmill in normal, virtual and augmented versions of the laboratory environment. A series of spatiotemporal parameters and lower-limb joint angles were compared between conditions. The center of pressure (CoP) ellipse area (95% confidence ellipse) was significantly different between conditions (p = 0.002). Pairwise comparisons indicated a significantly greater CoP ellipse area for both the AR (p = 0.002) and VR (p = 0.005) conditions when compared to the normal laboratory condition. Furthermore, there was a significant difference in stride length (p0.082), except for maximum ankle plantarflexion (p = 0.001). These differences in CoP ellipse area indicate that users of head-mounted VR/AR devices had difficulty maintaining a stable position on the treadmill. Also, differences in the gait parameters suggest that users walked with an unusual gait pattern which could potentially affect the effectiveness of gait rehabilitation treatments. Based on these results, position guidance in the form of feedback and the use of specialized treadmills should be considered when using head-mounted VR/AR devices

Measurement agreement between a newly developed sensing insole and traditional laboratory-based method for footstrike pattern detection in runners

This study introduced a novel but simple method to continuously measure footstrike patterns in runners using inexpensive force sensors. Two force sensing resistors were firmly affixed at the heel and second toe of both insoles to collect the time signal of foot contact. A total of 109 healthy young adults (42 males and 67 females) were recruited in this study. They ran on an instrumented treadmill at 0˚, +10˚, and -10˚ inclinations and attempted rearfoot, midfoot, and forefoot landings using real time visual biofeedback. Intra-step strike index and onset time difference between two force sensors were measured and analyzed with univariate linear regression. We analyzed 25,655 footfalls and found that onset time difference between two sensors explained 80–84% of variation in the prediction model of strike index (R-squared = 0.799–0.836, p<0.001). However, the time windows to detect footstrike patterns on different surface inclinations were not consistent. These findings may allow laboratory-based gait retraining to be implemented in natural running environments to aid in both injury prevention and performance enhancement

Patellofemoral pain during step descents with without fatigue-induced hip internal rotation

Weakness of hip external rotator muscles may cause excessive hip internal rotation during functional activity and it is associated with the development of patellofemoral pain (PFP). The aetiology of PFP is multifactorial in nature. Therefore, routine enrolment of patients into a hip-strengthening programme may not be effective and cost-effective. The present study examined the effect of fatigue-induced hip internal rotation during functional activity. Twenty subjects with PFP were asked to descend a step in barefoot before and after an isokinetic exercise protocol to induce muscle fatigue of hip external rotators. The hip motion was captured by eight high-speed cameras and analysed by a three-dimensional motion analysis system. The level of PFP during step descent and their usual PFP level were measured by validated instruments. Patients with PFP presented with more pronounced hip pathomechanics (p < 0.001) and greater level of PFP (p = 0.001) after muscle fatigue. The pain score after muscle fatigue during step descent better reflects the usual functional disturbance associated with PFP (rs = -0.655, p = 0.002). Physical examination with induced muscle fatigue may be helpful in clinical decisions on the management programme for patients with PFP, which are related to altered hip mechanics

Landing pattern and vertical loading rates during shod and barefoot running in habitual shod runners

There is evidence to support that habitual barefoot runners are able to disperse impact loading rates by landing pattern modification. However, case studies have been reported that barefoot running may cause stress fractures. It may be due to the immediate biomechanical response difference between habitual and novice barefoot runners. Therefore, purpose of this study was to examine the immediate effects of barefoot running in habitual shod runners. Thirty habitual shod runners were asked to run on an instrumented treadmill at 10km/hr in shod and barefoot. Vertical average (VALR) and instantaneous loading rates (VILR) were obtained by previously established methods. The landing pattern was presented as a ratio between number of footfall with heel-strike and the total step number. Twenty out of 30 participants demonstrated an automatic transition to a non-heel-strike landing. A mixed landing pattern was observed in 10 participants. Compared to shod running, both VALR and VILR significantly reduced during barefoot running (p<0.021). In the subgroup analysis, VALR for the shod condition was significantly higher than barefoot running, regardless of the state in the landing pattern transition. Furthermore, VALR for the non-heel-strike pattern during barefoot running was significantly lower than the condition of barefoot running with mixed landing pattern (mean difference=4.3; 95%CI 0.2-8.5). We observed the similar but marginal insignificant effect of footwear condition on VILR (p=0.066). Habitual shod runners presented lower loading rates during impact but their landing pattern transitions were not uniform. A kinetic evaluation after a transition program is thus recommended