BumChul Yoon

Unsupervised Virtual Reality-Based Exercise Program Improves Hip Muscle Strength and Balance Control in Older Adults: A Pilot Study

OBJECTIVE To assess the effects of an unsupervised virtual reality (VR)-based exercise program on hip muscle strength and balance control in older adults. DESIGN Controlled cohort repeated-measures experimental design, a pilot study. SETTING University research laboratory. PARTICIPANTS Ambulatory older adults (N=32) from a local community. INTERVENTION The VR group (n=18; mean ± SD, 68.28±3.74y; 4 men) completed the VR-based exercise program, whereas the remaining subjects in the control group (n=14; mean ± SD, 66.21±3.87y, 1 man) were asked to continue their daily routine for 8 weeks. MAIN OUTCOME MEASURES Hip muscle strength was measured using a multimodal dynamometer, and ground reaction force using the backward stepping test and the results of the crossover stepping test were recorded using a force platform. RESULTS The VR group showed significant improvement in hip muscle strength of the extensors, flexors, adductors, and abductors after 8 weeks (all P≤.001). However, no significant improvement was observed in the control group. The VR group had significantly greater ground reaction force on the backward stepping test (with eyes opened and closed) (all P<.005) and the crossover stepping test (with eyes opened and closed) (all P≤.001) compared with those at baseline. However, no significant improvement was observed in the control group. CONCLUSIONS The VR-based exercise program includes the role of supervisor and feedback, which is important for older adults. Therefore, a VR-based exercise program may be a useful tool to improve decreased physical function in older adults as a home-based exercise.

Tactile feedback plays a critical role in maximum finger force production.

This study investigates the role of cutaneous feedback on maximum voluntary force (MVF), finger force deficit (FD) and finger independence (FI). FD was calculated as the difference between the sum of maximal individual finger forces during single-finger pressing tasks and the maximal force produced by those fingers during an all-finger pressing task. FI was calculated as the average non-task finger forces normalized by the task-finger forces and subtracted from 100 percent. Twenty young healthy right-handed males participated in the study. Cutaneous feedback was removed by administering ring block digital anesthesia on the 2nd, 3rd, 4th and 5th digits of the right hands. Subjects were asked to press force sensors with maximal effort using individual digits as well as all four digits together, with and without cutaneous feedback. Results from the study showed a 25% decrease in MVF for the individual fingers as well as all the four fingers pressing together after the removal of cutaneous feedback. Additionally, more than 100% increase in FD after the removal of cutaneous feedback was observed in the middle and ring fingers. No changes in FI values were observed between the two conditions. Results of this study suggest that the central nervous system utilizes cutaneous feedback and the feedback mechanism plays a critical role in maximal voluntary force production by the hand digits.

A neuromuscular strategy to prevent spinal torsion: Backward perturbation alters asymmetry of transversus abdominis muscle thickness into symmetry

Symmetric co-contraction of the transversus abdominis (TrA) muscle is beneficial in terms of increasing trunk stability. The aim of this study was to investigate the symmetry of lateral abdominal muscle thickness during static and dynamic conditions. Fifteen male subjects (27.13 ± 5.51 years old) were instructed to sit on a chair and maintain upright posture. Every individual subject wore a jacket harness that could be backwardly attached to a 9-kg weight through a pulley system. An unexpected drop of the weight induced the transition from static to dynamic condition. The thickness of external oblique, internal oblique, and TrA muscles was measured with ultrasonography. Our results revealed more symmetry of TrA thickness during the dynamic condition (21% vs. 13%, p = 0.019) compared with the static. The symmetric muscle thickness of TrA during the dynamic condition is considered a result of more contraction on the non-dominant side. This phenomenon could be a possible strategy of deep abdominal muscles to prevent spinal torsion during sudden trunk perturbation.

The role of tactile sensation in online and offline hierarchical control of multi-finger force synergy.

The hand, one of the most versatile but mechanically redundant parts of the human body, must overcome imperfect motor commands and inherent noise in both the sensory and motor systems in order to produce desired motor actions. For example, it is nearly impossible to produce a perfectly consistent note during a single violin stroke or to produce the exact same note over multiple strokes, which we denote online and offline control, respectively. To overcome these challenges, the central nervous system synergistically integrates multiple sensory modalities and coordinates multiple motor effectors. Among these sensory modalities, tactile sensation plays an important role in manual motor tasks by providing hand-object contact information. The purpose of this study was to investigate the role of tactile feedback in individual finger actions and multi-finger interactions during constant force production tasks. We developed analytical techniques for the linear decomposition of the overall variance in the motor system in both online and offline control. We removed tactile feedback from the fingers and demonstrated that tactile sensors played a critical role in the online control of synergistic interactions between fingers. In contrast, the same sensors did not contribute to offline control. We also demonstrated that when tactile feedback was removed from the fingers, the combined motor output of individual fingers did not change while individual finger behaviors did. This finding supports the idea of hierarchical control where individual fingers at the lower level work together to stabilize the performance of combined motor output at the higher level.

Comparison of the effects of water- and land-based exercises on the physical function and quality of life in community-dwelling elderly people with history of falling: A single-blind, randomized controlled trial

PURPOSE The purpose of this study was to identify the effects of water-based exercises on the physical functions and quality of life (QOL) in community-dwelling elderly people with history of falling. MATERIALS AND METHODS Participants were randomly assigned to the water-based exercise group (n=34) or land-based exercise groups (n=32). To identify the effects on physical functions, muscle strength, flexibility, and mobility were measured. QOL and fear of falling were evaluated using the Short Form 36-item questionnaire and the modified falls efficacy scale (M-FES). The measurements were performed before and after the 10-week training period. RESULTS Within-group analysis indicated that hip abduction and adduction strength improved significantly in both groups (p=0.005; p=0.007). However, no statistically significant within-group differences were found in the back scratch test (p=0.766) and chair sit-and-reach test (p=0.870). QOL was significantly different in both groups (health transition: p=0.014, physical functioning: p<0.001, role physical: p<0.001, role emotional: p=0.002, bodily pain: p<0.001, vitality: p<0.001, and mental health: p<0.001). There was a significant difference in the M-FES in both groups (p=0.040). CONCLUSIONS These results indicate that water-based exercises are beneficial to improve the QOL, as well as physical activities, of community-dwelling elderly compared with land-based exercise. Water-based exercises would be useful to improve physical and psychological health in the elderly people with history of falling.

Individualized feedback-based virtual reality exercise improves older women's self-perceived health: A randomized controlled trial

OBJECTIVES Individualized feedback-based virtual reality (IFVR) exercise is gaining attention as a cost-effective self-management strategy, however little is known about whether older adults themselves perceive IFVR exercise effective in improving their health. Therefore, we studied the effect of IFVR exercise on health-related quality of life (HRQoL) in older women. METHODS Fifty-four older women aged ≥65 years were randomized to either IFVR exercise group (IFVRG, n=26) or group-based exercise group (GG, n=28). Both groups received a 60-min intervention three times a week for eight weeks. The Short-Form Health Survey (SF-36) was administered. To identify the possible placebo effect, 30-Second Chair Stand Test (30SCST), 8-Foot Up-and-Go Test (8FUGT), and 2-Minute Step Test (2MST) were also administered. RESULTS intention-to-treat analysis with adjustment for baseline levels revealed that IFVRG showed greater improvement in mental health (p=0.029) and lower body strength (p=0.042), compared to GG. Within-group analysis for HRQoL revealed that IFVRG showed an increase in role-physical (p=0.015), bodily pain (p=0.017), general health (p=0.004), vitality (p=0.010), role-emotional (p=0.007), and mental health (p<0.001), whereas GG showed an increase in role-physical (p=0.022), general health (p=0.023), and social functioning (p = 0.023). Both groups showed an increase in 30SCST, 2MST and 8FUGT (all p<0.001). CONCLUSION IFVR exercise improved HRQoL in older women, in addition to improving physical fitness. Therefore, it might be recommended to older women as an effective self-management strategy.

Effects of the high-power pain threshold ultrasound technique in the elderly with latent myofascial trigger points: A double-blind randomized study

BACKGROUND AND OBJECTIVE The high-power pain threshold ultrasound (HPPTUS) technique has been introduced as a novel treatment method in patients with myofascial trigger points (MTrPs). The aim of the current study was to compare the therapeutic effects of HPPTUS with those of the conventional ultrasound technique in elderly patients with latent MTrPs on the upper trapezius muscles of at least 1 side. MATERIAL AND METHODS Forty-one participants received 8 treatment sessions with conventional ultrasound (n=19) or with the HPPTUS technique (n=22) for 4 consecutive weeks. Outcome variables included visual analog scale (VAS) scores, pressure pain threshold (PPT), and range of motion (ROM). The data were analyzed using repeated analysis of variance (ANOVA) measurements. RESULTS The VAS scores recorded 1, 2, 3, and 4 weeks after HPPTUS were significantly lower than the baseline scores in both groups. The ROM (after 3 and 4 weeks) and PPT (after 4 weeks) values also significantly increased from their baseline values in both groups. On comparing the techniques, there were no significant differences in the VAS (p=0.296), PPT (p=0.768), and ROM (p=0.822) values, although both techniques showed therapeutic effects for 4 weeks (p < 0.001). CONCLUSION The results indicate that the HPPTUS technique in same manner as treatment of active MTrPs is not superior to the conventional ultrasound technique in the treatment of the elderly patients with the latent MTrPs.

Feasibility of a Self-Determination Theory-Based Exercise Program in Community-Dwelling South Korean Older Adults: Experiences from a 13-Month Trial

Little is known about the effectiveness of self-determination theory (SDT), a representative motivational theory, on exercise domain in older adults. This feasibility study used quantitative and qualitative approaches to evaluate the effectiveness of a 13-month group exercise program applying SDT-based motivational strategies on exercise adherence, physical fitness, and quality of life, and to explore factors affecting exercise adherence in South Korean older adults (N = 18). Exercise attendance rate was high (82.52%). There were significant differences in aerobic endurance (p < .001), lower body strength (p < .05), dynamic balance (p < .001), and perceived social functioning (p < .05) at 13 months compared with baseline. Factors affecting exercise adherence were related to the SDT-based motivational strategies. These results support the importance of health professionals applying SDT-based motivational strategies to exercise programs to help facilitate motivation for participation and to promote physical fitness and quality of life in older adults.

Long-term treadmill exercise-induced neuroplasticity and associated memory recovery of streptozotocin-induced diabetic rats: an experimenter blind, randomized controlled study.

We investigated a long-term exercise-induced neuroplasticity and spatial memory recovery in 15 rats in a treadmill as follows: normal control rats (NC), streptozotocin (STZ)-induced diabetic control rats (DC), and STZ-induced diabetic rats exercising in a treadmill (DE). As per the DE group, the running exercise in a treadmill was administered for 30 minutes a day for 6 weeks. Neuronal immediate-early gene (IEG) expression (c-Fos) in the hippocampus and radial arm maze (RAM) tests were measured and revealed that the c-Fos levels in DE were significantly higher than those in NC and DC (p < 0.05). Behavioral data analysis indicated that spatial memory performance scores, obtained from the RAM test, were significantly different among the three groups (p < 0.05). The memory scores of NC and DE were higher than those of DC (p < 0.05). These findings suggest that exercising in the treadmill increased neuronal immediate-early gene expression associated with neuroplasticity, thereby improving spatial memory. This is the first experimental evidence in literature that supports the efficacy of exercise-induced neuroplasticity and spatial motor memory in diabetes care.

Changes in Ankle Range of Motion and Muscle Strength in Habitual Wearers of High-Heeled Shoes

Background: Although cross-sectional biomechanical studies have reported that wearing high-heeled shoes can change the musculoskeletal system of the lower extremities, the long-term effects of wearing such shoes on the ankle remain unknown. The aim of this study was to reveal changes in ankle range of motion and muscle strength in habitual wearers of high-heeled shoes and to provide information for clinicians undertaking functional evaluations of the ankles of such patients. Methods: Habitual wearers of high-heeled shoes (n = 10; age, 23.9 ± 2.7 years) and wearers of flat shoes (n = 10; age, 23.8 ± 2.1 years) were selectively recruited, and the range of motion, maximal voluntary isometric force, and concentric contraction power of their ankles were measured. Results: Wearers of high-heeled shoes showed increased ankle range of motion on plantarflexion at 25 degrees and inversion at 10 degrees compared to flat shoe wearers (P < .05) but decreased dorsiflexion (about 17 degrees) and eversion (13 degrees; P < .05). Concentric contraction power in ankle eversion was also 2 times higher in wearers of high-heeled shoes (P < .05). Conclusions: These subjects had functional deformity of the ankle in a supinated direction and increased eversion power. Clinical Relevance: We cautiously recommend that habitual wearers of high-heeled shoes (those who walk in such shoes for more than 5 hours more than 6 times a week) undertake intensive ankle stretching exercises in the direction of dorsiflexion as well as eversion.