Direction-specific impairment of stability limits and falls in children with developmental coordination disorder: Implications for rehabilitation.

Limit of stability (LOS) is an important yet under-examined postural control ability in children with developmental coordination disorder (DCD). This study aimed to (1) compare the LOS and fall frequencies of children with and without DCD, and (2) explore the relationships between LOS parameters and falls in the DCD population. Thirty primary school-aged children with DCD and twenty age- and sex-matched typically-developing children participated in the study. Postural control ability, specifically LOS in standing, was evaluated using the LOS test. Reaction time, movement velocity, maximum excursion, end point excursion, and directional control were then calculated. Self-reported fall incidents in the previous week were also documented. Multivariate analysis of variance results revealed that children with DCD had shorter LOS maximum excursion in the backward direction compared to the control group (p=0.003). This was associated with a higher number of falls in daily life (rho=-0.556, p=0.001). No significant between-groups differences were found in other LOS-derived outcomes (p>0.05). Children with DCD had direction-specific postural control impairment, specifically, diminished LOS in the backward direction. This is related to their falls in daily life. Therefore, improving LOS should be factored into rehabilitation treatment for children with DCD.

Changes in heart-rate variability of survivors of nasopharyngeal cancer during Tai Chi Qigong practice.

[Purpose] To explore the changes in heart-rate variability (HRV) of survivors of nasopharyngeal cancer (NPC) before, during, and after a Tai Chi (TC) Qigong exercise. [Subjects and Methods] Eleven survivors of NPC participated voluntarily in the study. The heart rate of each participant was measured continuously for 1 minute before the TC Qigong intervention, during the 5-minute TC Qigong intervention, and for 1 minute after the intervention, using a Polar heart-rate monitor. Spectral HRV was expressed in terms of normalised low frequency (LF) power, normalised high frequency (HF) power, and the low frequency/high frequency (LF/HF) power ratio. [Results] Both the LF-power and the HF-power components had significant time effects. However, the time effect of the LF/HF power ratio was not significant. Post hoc contrast analysis revealed a significant decrease in LF power and a concomitant increase in HF power during the 4th minute and 5th minute of the TC Qigong exercise. [Conclusion] Five minutes of TC Qigong exercise was found to improve HRV by increasing HF power and decreasing LF power, but these effects were transient. TC Qigong might be an appropriate exercise for improving the ANS function and psychological and cardiac health of survivors of NPC.

Balance Performance in Irradiated Survivors of Nasopharyngeal Cancer with and without Tai Chi Qigong Training.

This cross-sectional exploratory study aimed to compare the one-leg-stance time and the six-minute walk distance among TC Qigong-trained NPC survivors, untrained NPC survivors, and healthy individuals. Twenty-five survivors of NPC with TC Qigong experience, 27 survivors of NPC without TC Qigong experience, and 68 healthy individuals formed the NPC-TC Qigong group, NPC-control group, and healthy-control group, respectively. The one-leg-stance (OLS) timed test was conducted to assess the single-leg standing balance performance of the participants in four conditions: (1) standing on a stable surface with eyes open, (2) standing on a compliant surface with eyes open, (3) standing on a stable surface with eyes closed, and (4) standing on a compliant surface with eyes closed. The six-minute walk test (6MWT) was used to determine the functional balance performance of the participants. Results showed that the NPC-control group had a shorter OLS time in all of the visual and supporting surface conditions than the healthy control group (P < 0.05). The OLS time of the TC Qigong-NPC group was comparable to that of the healthy control group in the somatosensory-challenging condition (condition 3) (P = 0.168) only. Additionally, there was no significant difference in the 6MWT distance among the three groups (P > 0.05). TC Qigong may be a rehabilitation exercise that improves somatosensory function and OLS balance performance among survivors of NPC.

Differential postural control and sensory organization in young tennis players and taekwondo practitioners.

This study compared the sensory organization and standing balance of adolescent tennis players, taekwondo (TKD) practitioners, and healthy control participants. Sixty participants including 12 tennis players, 21 TKD practitioners, and 27 healthy control participants were tested. All of the participants underwent the Sensory Organization Test (SOT) and the Unilateral Stance Test (UST) on a Smart Equitest system. Results revealed that tennis players had higher SOT visual ratios than the control participants (p = .005), and TKD practitioners swayed more slowly in the UST than the control participants (p = .039). No differences (p > .05) were found in the composite score, somatosensory ratio, or vestibular ratio between the groups. Tennis players swayed less when they relied more on visual input to maintain balance, whereas TKD practitioners were more stable when standing on one leg. Parents may consider these sports as recreational activities for their children to develop specific balance abilities.

Shoulder Mobility, Muscular Strength, and Quality of Life in Breast Cancer Survivors with and without Tai Chi Qigong Training.

Objectives. To compare the shoulder mobility, muscular strength, and quality of life (QOL) among breast cancer survivors with and without Tai Chi (TC) Qigong training to those of healthy individuals and to explore the associations between shoulder impairments and QOL in breast cancer survivors with regular TC Qigong training. Methods. Eleven breast cancer survivors with regular TC Qigong training, 12 sedentary breast cancer survivors, and 16 healthy participants completed the study. Shoulder mobility and rotator muscle strength were assessed by goniometry and isokinetic dynamometer, respectively. QOL was assessed using the Functional Assessment of Cancer Therapy-Breast (FACT-B) questionnaire. Results. Goniometric measurements of the active range of motion in the flexion, abduction, and hand-behind-the-back directions were similar among the three groups. The TC Qigong-trained breast cancer survivors had significantly higher isokinetic peak torques of the shoulder rotator muscles (at 180°/s) than untrained survivors, and their isokinetic shoulder muscular strength reached the level of healthy individuals. Greater shoulder muscular strength was significantly associated with better functional wellbeing in breast cancer survivors with TC Qigong training. However, no significant between-group difference was found in FACT-B total scores. Conclusions. TC Qigong training might improve shoulder muscular strength and functional wellbeing in breast cancer survivors.

Differential effect of Taekwondo training on knee muscle strength and reactive and static balance control in children with developmental coordination disorder: a randomized controlled trial.

This randomized controlled trial aimed to investigate the effect of short-term intensive TKD training on the isokinetic knee muscle strength and reactive and static balance control of children with developmental coordination disorder (DCD). Among the 44 children with DCD (mean age: 7.6 ± 1.3 years) recruited, 21 were randomly assigned to undergo daily TKD training for 1h over three consecutive months, with the remaining 23 children being assigned to the DCD control group. Eighteen typically developing children (mean age: 7.2 ± 1.0 years) received no training as normal controls. Knee extensor and flexor muscle strength and reactive and static balance control were assessed using an isokinetic machine (with low, moderate and high movement velocities), a motor control test (MCT) and a unilateral stance test (UST), respectively. A repeated measures MANCOVA revealed a significant group through time interaction effect in isokinetic outcomes at 180°/s and in the UST outcome. Post hoc analysis demonstrated that DCD-TKD children's isokinetic knee muscle strength, specifically at 180°/s, was as high as that of the normal control children (p>0.0083) after TKD training. Moreover, UST body sway velocity was slower in the DCD-TKD group than in the DCD control group (p<0.001), and was comparable to that of the normal control group (p>0.05) after TKD training. However, no such improvement in balance was observed in the MCT (p>0.025). The results show that children with DCD who undergo a 3-month program of intensive TKD training experience improvements in isokinetic knee muscle strength at 180°/s and static single-leg standing balance control, but do not benefit from improved reactive balance control.