This study determines the effect of walking backward on a treadmill on balance, speed of walking and cardiopulmonary fitness for patients with chronic stroke. Subjects with chronic stroke for more than six months, whose level of Brunnstrom stage is greater than IV and who are able to walk more than eleven meters with or without assistive devices were recruited. After grouping for a single-blind clinical randomized controlled trial, the subjects were divided into two groups: eight in the control group and eight in the experimental group. All subjects were subjected to 30 min traditional physical therapy, three times a week for four weeks. The experimental group was subjected to an additional 30 min of walking backward on a treadmill. The Berg Balance Scale (BBS) and the Timed Up and Go test (TUG) were used to determine the functional balance and walking ability. The walking speed was evaluated using a timed 10-Meter Walk Test (10MWT), and the cardiopulmonary fitness was determined using a 6-Minute Walk Test (6MWT) and a pulmonary function test (PFT). All assessments were made at baseline before training commenced (pre-training) and at the end of the four-week training period (post-training). A paired t-test and an independent t-test were used to determine the effect on balance, speed of walking and cardiopulmonary fitness before and after training. The level of significance α was 0.05. After four weeks of training, the experimental group showed significant differences (p < 0.05) on TUG, BBS, 10MWT, 6MWT, forced vital capacity (FVC) and forced expiratory volume in one second (FEV1). This pilot study shows that the 30 min of walking backward on a treadmill three times a week for four weeks increased balance, speed of walking and cardiopulmonary fitness. Trial registration: Current Controlled Trials NCT02619110.

Older adults with sarcopenia, which is an aging-related phenomenon of muscle mass loss, usually suffer from decreases in both strength and functional performance. However, the causality between function loss and physiological changes is unclear. This study aimed to explore the motor unit characteristics of the neurological factors between normal subjects and those with sarcopenia. Five risk-sarcopenia (age: 66.20 ± 4.44), five healthy (age: 69.00 ± 2.35), and twelve young (age: 21.33 ± 1.15) participants were selected. Each participant performed knee extension exercises at a 50% level of maximal voluntary isometric contraction. Next, electromyogram (EMG) signals were collected, and information on each parameter—e.g., motor unit number, recruitment threshold, the slope of the mean firing rate to recruitment threshold, y-intercept, firing rate per unit force, and mean motor unit firing rate (MFR)—was extracted to analyze muscle fiber discrimination (MFD). Meanwhile, force variance was used to observe the stability between two muscle groups. The results suggested that there was no difference between the three groups for motor unit number, recruitment threshold, y-intercept, mean firing rate, and motor unit discrimination (p > 0.05). However, the slope of MFR and firing rate per unit force in the risk-sarcopenia group were significantly higher than in the young group (p < 0.05). Regarding muscle performance, the force variance in the non-sarcopenia group was significantly higher than the young group (p < 0.05), while the risk-sarcopenia group showed a higher trend than the young group. This study demonstrated some neuromuscular characters between sarcopenia and healthy elderly and young people when performing the same level of leg exercise tasks. This difference may provide some hints for discovering aging-related strength and function loss. Future studies should consider combining the in vivo measurement of muscle fiber type to clarify whether this EMG difference is related to the loss of muscle strength or mass before recruiting symptomatic elderly participants for further investigation.

Purpose: To determine the effect of vibrating rollers on skin blood flow after running for recovery from muscle fatigue. Method: 23 healthy runners, aged between 20 to 45 years, participated in a crossover trial. Muscle fatigue was induced by running, and recovery using a vibrating roller was determined before and after the intervention. Each subject was measured at three time points (prerun, postrun, and postroller) to compare skin blood flow perfusion and blood flow oscillation at the midpoint of the dominant gastrocnemius muscle. The results show that blood perfusion is greater when a vibrating roller is used than a foam roller, but there is no statistical difference. The analysis of blood flow oscillation shows that vibrating rollers induce 30% greater endothelial activation than a foam roller. Vibrating rollers significantly stimulate the characteristic frequency for myogenic activation (p < 0.05); however, the effect size is conservative.

Background: The comparison between the mini-midvastus (mini-MV) and mini-parapatellar (mini-MPP) approach in total knee arthroplasty (TKA) remains a subject of debate. The present study compared quadriceps activation, pain levels, and clinical outcomes between the two approaches; quadricep activation was assessed using surface electromyography (sEMG). Methods: This retrospective cross-sectional study comprised a total of 78 patients aged between 50 and 85 years with primary osteoarthritis. Patients were divided into a mini-MV (n = 38) group and a mini-MPP (n = 40) group according to the surgical approach. Results: The two groups exhibited no significant differences in sEMG for the vastus medialis (VM) or rectus femoris (RF) at the follow-up time points, with the exception that the mini-MV group exhibited superior strength of RF during extensions at the 2-week follow-up. However, the mini-MPP group had superior Western Ontario and McMaster Universities Index (WOMAC) total and function scores at the 2- and 6-week follow-ups. The mini-MPP group also had superior WOMAC stiffness scores at the 2-week follow-up. The two groups did not differ significantly in terms of pain levels or morphine consumption. Conclusions: The sEMG data of quadriceps muscle would not differ significantly between the mini-MV and mini-MPP approaches for TKA. Moreover, the mini-MPP approach may yield superior WOMAC scores when compared with the mini-MV approach.

Since there is merit in noninvasive monitoring of muscular oxidative metabolism for near-infrared spectroscopy in a wide range of clinical scenarios, the present study attempted to evaluate the clinical usability for featuring the modulatory strategies of sternocleidomastoid muscular oxygenation using near-infrared spectroscopy in mild nonspecific neck pain patients. The muscular oxygenation variables of the dominant or affected sternocleidomastoid muscles of interest were extracted at 25% of the maximum voluntary isometric contraction from ten patients (5 males and 5 females, 23.6 ± 4.2 years) and asymptomatic individuals (6 males and 4 females, 24.0 ± 5.1 years) using near-infrared spectroscopy. Only a shorter half-deoxygenation time of oxygen saturation during a sternocleidomastoid isometric contraction was noted in patients compared to asymptomatic individuals (10.43 ± 1.79 s vs. 13.82 ± 1.42 s, p < 0.001). Even though the lack of statically significant differences in most of the muscular oxygenation variables failed to refine the definite pathogenic mechanisms underlying nonspecific neck pain, the findings of modulatory strategies of faster deoxygenation implied that near-infrared spectroscopy appears to have practical potential to provide relevant physiological information regarding muscular oxidative metabolism and constituted convincing preliminary evidences of the adaptive manipulations rather than pathological responses of oxidative metabolism capacity of sternocleidomastoid muscles in nonspecific neck patients with mild disability.

Introduction: This study investigated reactive agility performance in older adults and examined its associations with muscle‐related and functional factors. Methods: This cross‐sectional study included 114 community‐dwelling older adults with 110 valid reactive‐agility data. A modified functional reactive agility test (FRAT) provided total time (TT), decision time (DT), and movement time (MT) from each participant's shortest‐TT trial. Muscle health was characterized using skeletal muscle index (SMI) and handgrip strength, while functional performance was assessed separately using the five‐times sit‐to‐stand test (5STST). Between‐group differences were tested using one‐way or Welch analysis of variance as appropriate. Separate multivariable models were fitted for TT, DT, and MT, with multiple‐testing correction. Results: Minimum‐TT trial outcomes did not differ among the four muscle‐health groups. In the multivariable models, slower 5STST performance was consistently associated with longer TT ( β = 0.48), DT ( β = 0.37), and MT ( β = 0.44), with all associations remaining significant after false‐discovery‐rate correction (all q < 0.001). No other examined covariate remained significantly associated with reactive agility outcomes after multiple‐testing correction. Variance decomposition of TT showed that the MT variance term constituted the largest component of between‐participant variability (70.2%), compared with the DT variance (10.4%) and DT–MT covariance (19.4%) terms. Conclusion: Reactive agility did not differ significantly among muscle‐health groups, whereas 5STST performance was consistently associated with TT, DT, and MT. Movement time represented the largest component of between‐participant variability in TT, suggesting that functional performance and temporal components may offer complementary information for characterizing reactive agility in older adults.