A walking program improves gait and balance in nursing home patients

Pedometer determined ambulatory activity and bone mass: a population-based longitudinal study in older adults

In this large population-based study, walking was assessed twice yearly for a week, each time by pedometer, had consistent clinically important associations with hip areal bone mineral density (aBMD) in both sexes which appears most important in those over 65 years of age suggesting that walking becomes more important with increasing age.

INTRODUCTION

Walking is advocated as a preventative strategy for osteoporosis but the evidence is conflicting in females and lacking in males. The aim of this population-based longitudinal study in community dwelling older people (n=875) was to determine the association between pedometer determined ambulatory activity (PAA) and bone mass.

METHODS

Bone mass was assessed as aBMD at the hip and spine using dual X-ray absorptiometry. Steps per day were measured using pedometers for 1 week on four occasions at least 6 months apart. Data were analysed using linear mixed models.

RESULTS

At baseline, PAA was positively associated with hip aBMD. An age interaction was present with steps having a stronger association for those aged over 65 years. Longitudinally, the effect of steps on hip aBMD was constant, but not additive over time. For those over 65 years, the difference in hip aBMD between the lowest and highest steps quartiles ranged from 3.1% to 9.4%. With regard to the spine, the relationship between daily steps and spine aBMD was modified by sex. For males; there was no significant relationship between steps and spine aBMD. However, for females, higher steps were associated with higher spine aBMD with the effect being constant over time but not additive. There was no evidence of a threshold effect.

CONCLUSION

In conclusion, pedometer-determined ambulatory activity has consistent clinically important associations with hip aBMD in both sexes which appears most important in those over 65 years of age. The associations for spine aBMD were both weaker and inconsistent suggesting site specificity.

Spatial, temporal and muscle action patterns of Tai Chi gait

This study was to quantitatively characterize the spatial, temporal, and neuromuscular activation patterns of Tai Chi gait (TCG). Ten healthy young subjects were tested. The kinematics of TCG and normal gait (NG) were measured using a marker-based motion analysis system and two biomechanical force plates. Surface electromyography (EMG) was recorded from six left-side muscles: tibialis anterior, soleus, peronaeus longus, rectus femoris, semitendinosus, and tensor fasciae latae. The results showed that TCG had (1) a longer cycle duration (11.9+/-2.4 vs. 1.3+/-0.2 s) and a longer duration of single-leg stance time (1.8+/-0.6 vs. 0.4+/-0.05 s); (2) a larger joint motion in ankle dorsi/plantar flexion (40+/-9 degrees vs. 20+/-8 degrees), knee flexion (82+/-8 degrees vs. 53+/-10 degrees), hip flexion (81+/-7 degrees vs. 24+/-4 degrees), and hip abduction (20+/-8 degrees vs. 0+/-3 degrees); (3) a larger lateral body shift (>25% vs. 5% body height); and (4) significant involvement of ankle dorsiflexors, knee extensors/hip flexors and hip abductors, as indicated by significantly higher peak (88+/-14%, 80+/-18% and 83+/-17% vs. 35+/-10%, 14+/-8% and 28+/-19% peak amplitude, respectively) and root-mean-square values of their EMG (37+/-6%, 32+/-7% and 33+/-7% vs. 23+/-7%, 11+/-8% and 22+/-11% peak amplitude, respectively), longer proportions of action (76+/-19%, 68+/-8% and 65+/-19% vs. 59+/-23%, 16+/-23% and 40+/-32% gait cycle duration, respectively), longer proportions of isometric and eccentric actions, and longer proportions of co-activations. These results demonstrate that the biomechanical characteristics of TCG can be quantified. The quantification of TCC movements is important for understanding its effect on balance, flexibility, strength, and health.

Sarcopenia

Sarcopenia is a term utilized to define the loss of muscle mass and strength that occurs with aging. Sarcopenia is believed to play a major role in the pathogenesis of frailty and functional impairment that occurs with old age. Progressive muscle wasting occurs with aging. The prevalence of clinically significant sarcopenia is estimated to range from 8.8% in young old women to 17.5% in old old men. Persons who are obese and sarcopenic (the "fat frail") have worse outcomes than those who are sarcopenic and non-obese. There is a disproportionate atrophy of type IIa muscle fibers with aging. There is also evidence of an age-related decrease in the synthesis rate of myosin heavy chain proteins, the major anabolic protein. Motor units innervating muscle decline with aging, and there is increased irregularity of muscle unit firing. There are indications that cytokines-especially interleukin-1beta, tumor necrosis factor-alpha, and interleukin-6-play a role in the pathogenesis of sarcopenia. Similarly, the decline in anabolic hormones-namely, testosterone, dehydroepiandrosterone growth hormone, and insulin-like growth factor-I-is also implicated in the sarcopenic process. The role of the physiologic anorexia of aging remains to be determined. Decreased physical activity with aging appears to be the key factor involved in producing sarcopenia. An increased research emphasis on the factors involved in the pathogenesis of sarcopenia is needed.