Immediately Effects of Static Stretching of the Ankle Plantar Flexor for 5 Minutes on Balance Control and Muscle Activity in Healthy Young Adults

Employing dynamic office chairs might increase the physical (micro-) activity during prolonged office sitting. We investigated whether a dynamic BioSwing® chair increases chair sway and alters trunk muscle activation. Twenty-six healthy young adults performed four office tasks (reading, calling, typing, hand writing) and transitions between these tasks while sitting on a dynamic and on a static office chair. For all task-transitions, chair sway was higher in the dynamic condition (p < 0.05). Muscle activation changes were small with lower mean activity of the left obliquus internus during hand writing (p = 0.07), lower mean activity of the right erector spinae during the task-transition calling to hand writing (p = 0.036), and higher mean activity of the left erector spinae during the task-transition reading to calling (p = 0.07) on the dynamic chair. These results indicate that an increased BioSwing® chair sway only selectively alters trunk muscle activation. Adjustments of chair properties (i.e., swinging elements, foot positioning) are recommended.

Download Full-text

Effects of Cognitive Over Postural Demands on Upright Standing Among Young Adults

Perceptual and Motor Skills ◽

10.1177/0031512520972879 ◽

2020 ◽

pp. 003151252097287

Author(s):

Kell Grandjean da Costa ◽

Erika K. Hussey ◽

Eduardo Bodnariuc Fontes ◽

Alekya Menta ◽

John W. Ramsay ◽

...

Keyword(s):

Young Adults ◽

Balance Control ◽

Healthy Adults ◽

Body Sway ◽

Cognitive Resources ◽

Stance Control ◽

Upright Standing ◽

Measurement Units ◽

Future Work ◽

The Impact

A growing body of research has shown that static stance control (e.g., body sway) is influenced by cognitive demands (CD), an effect that may be related to competition for limited central resources. Measures of stance control have also been impacted by postural demands (PD) (e.g., stable vs. unstable stances). However, less is known of any possible interactions between PD and CD on static stance control in populations with intact balance control and ample cognitive resources, like young healthy adults. In this study, among the same participants, we factorially compared the impact of PD with and without CD on static stance control. Thirty-four healthy young adults wore inertial measurement units (IMU) while completing static stance tasks for 30 seconds in three different PD positions: feet apart, feet together, and tandem feet. After completing these tasks alone, participants performed these tasks with CD by concurrently completing verbal serial seven subtractions from a randomly selected three-digit number. For two dependent measures, path length and jerk, there were main effects of CD and PD but no interaction effect between these factors. For all other stance control parameters, there was only a PD main effect. Thus, adding a cognitive demand to postural demands, while standing upright, may have an independent impact on stance control, but CD does not seem to interact with PD. These results suggest that young healthy adults may be less sensitive to simple PD and CD due to their greater inherent balance control and available cognitive resources. Future work might explore more complex PD and CD combinations to determine the boundaries under which young adults’ resources are taxed.

Download Full-text

Age-related neuromuscular function and dynamic balance control during slow and fast balance perturbations

Journal of Neurophysiology ◽

10.1152/jn.00476.2013 ◽

2013 ◽

Vol 110 (11) ◽

pp. 2557-2562 ◽

Cited By ~ 3

Author(s):

Jarmo M. Piirainen ◽

Vesa Linnamo ◽

Neil J. Cronin ◽

Janne Avela

Keyword(s):

Sensory Feedback ◽

Center Of Pressure ◽

Balance Control ◽

Dynamic Balance ◽

Neuromuscular Function ◽

Plantar Flexor ◽

Fast Recovery ◽

M Wave ◽

Age Related ◽

Wave Latency

This study investigated age-related differences in dynamic balance control and its connection to reflexes and explosive isometric plantar flexor torque in 19 males (9 Young aged 20–33 yr, 10 Elderly aged 61–72 yr). Dynamic balance was measured during Slow (15 cm/s) and Fast (25 cm/s) anterior and posterior perturbations. H/M-ratio was measured at 20% of maximal M-wave (H/M20%) 10, 30, and 90 ms after perturbations. Stretch reflexes were measured from tibialis anterior and soleus during anterior and posterior perturbations, respectively. In Slow, Elderly exhibited larger peak center-of-pressure (COP) displacement (15%; P < 0.05) during anterior perturbations. In Fast, Young showed a trend for faster recovery (37%; P = 0.086) after anterior perturbations. M-wave latency was similar between groups (6.2 ± 0.7 vs. 6.9 ± 1.2 ms), whereas Elderly showed a longer H-reflex latency (33.7 ± 2.3 vs. 36.4 ± 1.7 ms; P < 0.01). H/M20% was higher in Young 30 ms after Fast anterior (50%; P < 0.05) and posterior (51%; P < 0.05) perturbations. Plantar flexor rapid torque was also higher in Young (26%; P < 0.05). After combining both groups' data, H/M20% correlated negatively with Slow peak COP displacement ( r = −0.510, P < 0.05) and positively with Fast recovery time ( r = 0.580, P < 0.05) for anterior perturbations. Age-related differences in balance control seem to be more evident in anterior than posterior perturbations, and rapid sensory feedback is generally important for balance perturbation recovery.

Download Full-text

Older adults learn less, but still reduce metabolic cost, during motor adaptation

Journal of Neurophysiology ◽

10.1152/jn.00401.2013 ◽

2014 ◽

Vol 111 (1) ◽

pp. 135-144 ◽

Cited By ~ 28

Author(s):

Helen J. Huang ◽

Alaa A. Ahmed

Keyword(s):

Older Adults ◽

Young Adults ◽

Muscle Activity ◽

Motor Adaptation ◽

Metabolic Cost ◽

Gas Analysis ◽

The Novel ◽

Age Related ◽

Expired Gas Analysis ◽

Expired Gas

The ability to learn new movements and dynamics is important for maintaining independence with advancing age. Age-related sensorimotor changes and increased muscle coactivation likely alter the trial-and-error-based process of adapting to new movement demands (motor adaptation). Here, we asked, to what extent is motor adaptation to novel dynamics maintained in older adults (≥65 yr)? We hypothesized that older adults would adapt to the novel dynamics less well than young adults. Because older adults often use muscle coactivation, we expected older adults to use greater muscle coactivation during motor adaptation than young adults. Nevertheless, we predicted that older adults would reduce muscle activity and metabolic cost with motor adaptation, similar to young adults. Seated older ( n = 11, 73.8 ± 5.6 yr) and young ( n = 15, 23.8 ± 4.7 yr) adults made targeted reaching movements while grasping a robotic arm. We measured their metabolic rate continuously via expired gas analysis. A force field was used to add novel dynamics. Older adults had greater movement deviations and compensated for just 65% of the novel dynamics compared with 84% in young adults. As expected, older adults used greater muscle coactivation than young adults. Last, older adults reduced muscle activity with motor adaptation and had consistent reductions in metabolic cost later during motor adaptation, similar to young adults. These results suggest that despite increased muscle coactivation, older adults can adapt to the novel dynamics, albeit less accurately. These results also suggest that reductions in metabolic cost may be a fundamental feature of motor adaptation.

Download Full-text

Adding Light Touch While Walking in Older Adults: Biomechanical and Neuromotor Effects

Journal of Aging and Physical Activity ◽

10.1123/japa.2019-0270 ◽

2020 ◽

Vol 28 (5) ◽

pp. 680-685

Author(s):

Alison R. Oates ◽

Aaron Awdhan ◽

Catherine Arnold ◽

Joyce Fung ◽

Joel L. Lanovaz

Keyword(s):

Older Adults ◽

Muscle Activity ◽

Balance Control ◽

Center Of Mass ◽

Gait Pattern ◽

Light Touch ◽

Margin Of Stability ◽

Complex Picture ◽

Falls In Older Adults ◽

Haptic Input

Adding haptic input may improve balance control and help prevent falls in older adults. This study examined the effects of added haptic input via light touch on a railing while walking. Participants (N = 53, 75.9 ± 7.9 years) walked normally or in tandem (heel to toe) with and without haptic input. During normal walking, adding haptic input resulted in a more cautious and variable gait pattern, reduced variability of center of mass acceleration and margin of stability, and increased muscle activity. During tandem walking, haptic input had minimal effect on step parameters, decreased lower limb muscle activity, and increased cocontraction at the ankle closest to the railing. Age was correlated with step width variability, stride length variability, stride velocity, variability of medial-lateral center of mass acceleration, and margin of stability for tandem walking. This complex picture of sensorimotor integration in older adults warrants further exploration into added haptic input during walking.

Download Full-text