Delayed Impairment of Postural, Physical, and Muscular Functions Following Downhill Compared to Level Walking in Older People

Abstract

Transient symptoms of muscle damage emanating from unaccustomed eccentric exercise can adversely affect muscle function and potentially increase the risk of falling for several days. Therefore, the aims of the present study were to investigate the shorterand longer-lasting temporal characteristics of muscle fatigue and damage induced by level (i.e., concentrically biased contractions) or downhill (i.e., eccentrically biased contractions) walking on postural, physical, and muscular functions in older people. Nineteen participants were matched in pairs for sex, age and self-selected walking speed and allocated to a level (n = 10, age = 72.3 ± 2.9 years) or downhill (n = 9, age = 72.1 ± 2.2 years) walking group. Postural sway, muscle torque and power, physical function (5× and 60 s sit-to-stand; STS), and mobility (Timed-Up-and-Go; TUG) were evaluated at baseline (pre-exercise), 1 min, 15 min, 30 min, 24 h, and 48 h after 30 min of level (0% gradient) or downhill (−10% gradient) walking on a treadmill. Following downhill walking, postural sway (+66 to 256%), TUG (+29%), 60 s STS (+29%), five times STS (−25%) and concentric power (−33%) did not change at 1-30 min post exercise, but were significantly different (p < 0.05) at 24 and48 h postexercise when compared to baseline (p < 0.05). Muscle torque decreased immediately after downhill walking and remained impaired at 48 h post-exercise (−27 to −38%). Immediately following level walking there was an increase in postural sway (+52 to +98%), slower TUG performance (+29%), fewer STS cycles in 60 s (−23%), slower time to reach five STS cycles (+20%) and impaired muscle torque (−23%) and power (−19%) which returned to baseline 30-min after exercise cessation (p > 0.05). These findings have established for the first time distinct impairment profiles between concentric and eccentric exercise. Muscle damage emanating from eccentrically biased exercise can lead to muscle weakness, postural instability and impaired physical function persisting for several days, possibly endangering older adult's safety during activities of daily living by increasing the risk of falls.

The acute and repeated bout effects of multi-joint eccentric exercise on physical function and balance in older adults

“…The lack of change in any balance metric may be indicative that the eccentric exercise did not induce muscle fatigue, possibly a consequence of the low metabolic demand (Hoppeler 2016 ). To the authors’ knowledge, only Hill et al ( 2020 ) have assessed the short-term effects of eccentric exercise on older adults’ postural stability, reporting that immediately after 30 min of downhill walking their postural stability was unaffected, which concurs with the findings of the present study. Conversely, Hill et al ( 2020 ) also reported that balance was impaired at 24 and 48 hr post-exercise, although these disparate findings are likely a consequence of the exercise volume and/or type of eccentric exercise as Hill et al ( 2020 ) prescribed a substantial volume to induce muscle damage (downhill walking for 30 min), unlike the present study that utilised 5 min on a recumbent stepper.…”

“…To the authors’ knowledge, only Hill et al ( 2020 ) have assessed the short-term effects of eccentric exercise on older adults’ postural stability, reporting that immediately after 30 min of downhill walking their postural stability was unaffected, which concurs with the findings of the present study. Conversely, Hill et al ( 2020 ) also reported that balance was impaired at 24 and 48 hr post-exercise, although these disparate findings are likely a consequence of the exercise volume and/or type of eccentric exercise as Hill et al ( 2020 ) prescribed a substantial volume to induce muscle damage (downhill walking for 30 min), unlike the present study that utilised 5 min on a recumbent stepper. Collectively, these data indicate that the volume of exercise may be an important variable to control when prescribing specific eccentric exercise modes for older adults and that multi-joint low-volume and submaximal eccentric exercise can be performed by older adults without short-term reductions in static balance.…”

“…Symptoms of EIMD include delayed onset muscle soreness (DOMS), elevated blood serum molecular markers (e.g. creatine kinase), muscle weakness, and impaired balance (Hyldahl and Hubal 2014 ; Hody et al 2019 ; Hill et al 2020 ). Reductions in peak strength have been labelled as the most reliable measure of EIMD (Hyldahl and Hubal 2014 ) as they represent damage to the neuromuscular system.…”

Effectiveness of eccentric-biased exercise interventions in reducing the incidence of falls and improving functional performance in older adults: a systematic review

“…A trial by Hill et al fits the pre-determined eligibility criteria [ 21 ]. The findings of the paper suggested that eccentric interventions increase the risk of falls and degrade functional performance in older adults.…”

Effects of Flywheel Training With Eccentric Overload on Standing Balance, Mobility, Physical Function, Muscle Thickness, and Muscle Quality in Older Adults

“…First, given the high muscle forces that can be achieved during the eccentric phase, this exercise may cause temporary muscle damage. Muscle damage resulting from eccentric exercise can lead to muscle weakness, postural instability, and impaired physical function which can persist for several days, endangering older adult's safety during daily activities and potentially increase the risk of falls (13). Second, although coordination and technical demand of flywheel exercise may increase the risk of injury, the use of a harness and holding onto a secure structure for balance, as used in this study, likely reduces the technical skills necessary for proper movement execution.…”