Characterization of Vertical Accelerations Experienced by Older People Attending an Aerobics Class Designed to Produce High Impacts

Abstract

The purpose of this study was to establish the feasibility of using an aerobics class to produce potentially bone protective vertical impacts of ≥ 4g in older adults and to determine whether impacts can be predicted by physical function. Participants recruited from older adult exercise classes completed an SF-12 questionnaire, short physical performance battery, and an aerobics class with seven different components, performed at low and high intensity. Maximum g and jerk values were identified for each activity. Forty-one participants (mean 69 years) were included. Mean maximal values approached or exceeded the 4g threshold for four of the seven exercises. In multivariate analyses, age (-0.53; -0.77, -0.28) (standardized beta coefficient; 95% CI) and 4-m walk time (-0.39; -0.63, -0.16) were inversely related to maximum g. Aerobics classes can be used to produce relatively high vertical accelerations in older individuals, although the outcome is strongly dependent on age and physical function.

Habitual levels of higher, but not medium or low, impact physical activity are positively related to lower limb bone strength in older women: findings from a population-based study using accelerometers to classify impact magnitude

“…A possible explanation for this limited association is that the quartile of our study population with the greatest number of high impacts only experienced approximately 15 vertical impacts >1.5 g daily. In terms of the activities responsible for high impacts, 1.5 g exceeds that associated with walking (typically 0.5–1.0 g), but is achieved in the majority of aerobics class exercises undertaken by older individuals, particularly those with a jumping component [ 23 ]. Aerobics exercise participation was one of the commonest forms of high-impact PA in COSHIBA as assessed by questionnaire, and presumably contributed to the positive relationship we observed between impacts >1.5 g and lower limb bone strength [ 24 ].…”

“…Alternatively, the weak associations we observed could be a reflection of the relatively low levels of impact involved, and it may be that stronger impacts, closer to the 4-g osteogenic threshold identified in studies of younger individuals, are required to produce a significant benefit in terms of bone strength and fracture risk. Though impacts of this level are rarely achieved in unselected individuals, in our previous exercise study, we found that impacts within this range are readily achievable with only minor modifications to the class protocol [ 23 ].…”

Associations of lifetime walking and weight bearing exercise with accelerometer-measured high impact physical activity in later life

“…To this end, supporting both walking and weight bearing exercises, including activities like tennis and dancing ( Hannam et al, 2016b ), from midlife may be important for an active and functional older life including better skeletal health by promoting both overall and higher impact PA in later life. In addition, aerobics classes may provide a safe way for older adults to achieve exposure to higher impacts ( Hannam et al, 2016c ). In conclusion, we found that cumulative exposure to walking and weight bearing exercise across life was related to greater levels of higher impact PA in later life, and that associations were strongest from midlife.…”

“…Activity data were normalised based on seven valid days (≥ 10 h recording time) of 14 h. Y-axis peaks were calculated based on accelerations higher than the preceding and subsequent reading and recorded within 14 pre-specified g bands. We defined high impact PA as vertical acceleration peaks ≥ 1.5 g, where g values represent g over and above 1 g from earth's gravitational force, and was previously validated in older adults attending an exercise class ( Hannam et al, 2016c ). The ≥ 1.5 g cut-point for higher impacts was selected as very few impacts were observed within higher g bands ( Deere et al, 2016 , Hannam et al, 2016a , Hannam et al, 2016b ).…”

“…(e.g. running, racquet sports, football, rugby, hockey and dancing – not including walking, cycling or swimming), which are activities that have been shown to produce higher impacts ( Hannam et al, 2016c , Hannam et al, 2016b ). Possible responses were none, occasionally (once a month), frequently (once a week) or very frequently (more than once a week).…”