Physical activity interventions and falls

In addition to physical activity history, research has been conducted into specific physical activity programmes, normally in the form of structured exercise, as

intervention measures to reduce the risk of falling. As with the historical studies, falls themselves have often not been the outcome measure, and many of these studies have used measures of balance, gait and strength as indicators of success.

Of the studies that have used falls as an outcome measure, a 12-month general physical activity programme incorporating aerobic, strengthening and balance

exercises did not result in any significant differences in fall rates between the physical activity and control groups in the follow-up period (Lord et al. 1995). However, there was a trend for participants who attended 75% or more of the classes

experiencing fewer falls than those who attended less than 75% of the classes and the control group. As the physical activity classes were held twice weekly, it is possible that more frequent sessions, in line with physical activity recommendations, may have resulted in a significant reduction in fall occurrence. A 2-year home-based physical activity programme resulted in lower fall rates in women over 80 compared to a control group, as well as lower hazard rates for a moderate or serious injury

(Campbell et al. 1999). This type of programme has the advantage in that it is home-based and therefore not dependent on services such as transport and local facilities.

However, a home-based programme lacks a social element and may have lower adherence rates (Taylor et al. 2004). There were significantly fewer falls in a Tai Chi group than a stretching programme control group in the 6-month post-intervention follow-up after a 6-month intervention programme (Li et al. 2004), and a statistically significant 44% reduction in injurious falls after a 12-month Tai Chi intervention compared to the control group (Lin et al. 2006). There was a 25% reduction in falls in participants who participated in a 12-month intervention including strength,

balance and flexibility exercises compared to a control group, although this reduction was not statistically significant (Shumway-Cook et al. 2007). A meta-analysis of intervention studies suggests that programmes that include balance training are important for the efficacy of an intervention (Sherrington et al. 2008). This may partly explain why Tai Chi has proved a successful activity for falls prevention studies as this modality involves a substantial balance training element.

There are some reports, however, that suggest increased physical activity can actually increase the risk of falls. In a study utilising brisk walking as an intervention to reduce osteoporotic fractures, there was a significantly higher fall rate in the walking

group in the first 12 months (Ebrahim et al. 1997). However, despite the number of falls being higher in the walking group than the control group, the fracture rates were the same. In addition, during the following 12 months, the rate of falls had dropped below that of the control group, although the result was not significant. The definition of “brisk walking” in this study is vague; it is possible that initially the walking speed was at a pace that the participants found difficult to maintain postural control and therefore increased the likelihood of a fall. Once a training effect had been imparted, the risk of falling decreased, as can be seen by the lower rate of falls in the second year. Walking is also associated with a decreased risk of fracture in post-menopausal women (Feskanich et al. 2002) and a lower risk of cognitive decline in elderly women (Yaffe et al. 2001), therefore is clearly an important mode of activity.

However, care has to be exercised when prescribing activity so as not to place

individuals at a significantly increased risk of falling due to increased or inappropriate physical activity modality or intensity.

These studies suggest that physical activity intervention programmes have variable success in reducing the incidence of fall occurrence, and indicate that falls themselves are able to be used as an outcome measure in programmes of this nature. However, as falls are multifactorial in nature (Tinetti, 2003) it may not be that surprising that intervention related reductions in falls are not always statistically significant,

particularly in the short-term (6-12 months). So it is important with these intervention studies to not only use falls as an outcome measure but also to utilise measures of balance, strength and mobility as secondary outcome measures, as these are

associated with an increased risk of experiencing a fall and also will provide useful

information on the functional changes that have occurred that may contribute to any decreased fall risk.

Of the studies that have investigated other outcome measures, Tai Chi is the most frequently investigated form of physical activity intervention programme. Six-month Tai Chi interventions have resulted in improved functional balance compared to baseline (Li et al. 2004), and increased concentric and eccentric strength of the knee extensors (Lan et al. 2000). These strength increases may have implications for activities of daily living such as rising from a chair and also stability during gait.

However, the internal validity of Lan et al.’s study was weakened by the lack of a control group which may be due to it only being a pilot study. A 20-week Tai Chi intervention resulted in improvements in force control (Christou et al. 2003), which may result in more accurate body movements. A 12-month Tai Chi programme resulted in improved cardiorespiratory function, strength and flexibility compared to baseline, whilst a control group showed no changes (Lan et al. 1998). These studies demonstrate that Tai Chi is of value as an intervention tool for both increasing strength and balance ability which are associated with fewer falls and with lower fall occurrence as well.

Of the intervention studies that have used alternatives to Tai Chi, a 12-month general physical activity programme resulted in improved strength and reaction time

compared to baseline (Lord et al. 1995). A 20-week community-based physical activity programme incorporating strength, postural and stretching exercise resulted in improved knee extensor strength and increased gait speed around a figure-eight circuit in a group of older women with osteoporosis (Carter et al. 2002). Another 20-week

physical activity intervention class incorporating balance, strength, trunk stability and flexibility exercises resulted in significant improvements in balance measures and in the strength of the hip muscle, the quadriceps and the trunk extensors in community-dwelling women with osteopenia (Hourigan et al. 2008). A 16-week home-based intervention programme incorporating, balance, aerobic, strength and flexibility exercises improved performance on mobility tests and strength in the musculature of the ankle and reduced fear of falling (Delbaere et al. 2006a). A 10-week feasibility study using tango dancing resulted in gains in muscle strength demonstrated through sit-to-stand measures (McKinley et al. 2008). Intervention studies are often difficult to compare for efficacy as they utilise different intervention lengths, different

frequencies of classes and different outcome measures. Research is needed to identify the minimum frequency and duration of intervention programmes to assess the

efficacy for reducing fall risk. In addition to using falls themselves as an outcome measure, other outcome measures that are sensitive enough to discriminate between fallers and non-fallers in both healthy and frail older populations warrant further investigation. This would allow standardisation of these research trials and therefore the comparison of the relative merits of different physical activity programmes in different groups of older adults. The studies conducted to date do, however, show that significant improvements can be made through physical activity interventions that can modify associated risk factors for falling as well as reduce the associated fear of falling. The use of physical activity as a means to curb the number of falls in older people therefore warrants further attention.

Adherence to physical activity interventions is an important factor to consider when proposing the value of the programme in reducing falls and fall risk. The drop-out

rate from one 12-month Tai Chi study was 26.9% (Lan et al. 1998). The compliance rate from a home-based physical activity programme after 2 years was 44%

(Campbell et al. 1999), but as the population group were all over 80 this relatively low compliance rate after such a time period is perhaps unsurprising. A drop-out rate of only 12% was reported in a 20-week intervention study (Hourigan et al. 2008).

This intervention programme was community-based with flexibility over times and days of class attendance, with emphasis on social interaction, which may have

contributed to the high adherence levels observed to this programme. The drop-out of a home-based intervention was 30%, but this was attributed mainly to the participants bearing a fairly considerable financial cost (100 Euro) to take part as physiotherapists were involved at the beginning and end of the intervention period (Delbaere et al.

2006a). These studies indicate that many factors may be involved in the success of an intervention programme, and that it is possible that the success will be affected by the age of the target group, and that programmes that are relatively inexpensive and have a social aspect are likely to be the most successful. Six months after the intervention programme had ended, 66% of the Tai Chi group were still engaged in some Tai Chi or other exercise training (Li et al. 2004), and 10 years after a walking intervention participants were still walking significantly greater distances recreationally than the controls (Pereira et al. 1998), demonstrating that interventions can lead to permanent patterns of activity and therefore lifestyle changes.

These intervention studies show some positive results for reducing fall rates and improving functional performance. However, there has also been suggestion that physical activity and the risk of falling could have a U-shaped relationship, with those least active and most active at the greatest risk of falling (Gregg et al. 2000).

Therefore, care has to be exercised when encouraging increased physical activity to not expose the individual to a significantly increased risk of falling, whilst

maintaining the desired benefits from the activity. In further support of physical activity, there was a reduced risk of fracture in fallers with increasing amount of physical activity in the previous year (Keegan et al. 2004). This suggests that not only can physical activity have a preventative effect against falling in the first place, but also those who are active and are still unfortunate enough to experience a fall may also have a decreased risk of a fracture as an outcome. Therefore, any increased risk of falling in the most active, may be partly offset by the reduced risk of fracture as an outcome. However, adherence to these programmes may not always be that high and there is limited data on whether these programmes are continued after a study has ended. Therefore, it would be more advantageous to promote a healthy active

lifestyle in younger generations to achieve lifestyle changes that impact on fall risk in older age than wait until these groups are already in the “at risk” category for falls.