Cadence, energy expenditure, and gait symmetry during music-prompted and self-regulated walking in adults with unilateral transtibial amputation.

BACKGROUND: Walking cadence has shown promise for estimating walking intensity in healthy adults. Auditory cues have been shown to improve gait symmetry in populations with movement disorders. We investigated the walking cadence-energy expenditure relationship in unilateral transtibial amputees (TTAs), and the potential of music cues for regulating walking cadence and improving gait symmetry. METHODS: Seventeen unilateral TTAs performed 2 5-min treadmill walking trials, followed by 2 5-min overground walking trials (self-regulated "brisk" intensity, and while attempting to match a moderate-tempo digital music cue). RESULTS: Walking cadence significantly (P < .001) and accurately (R(2) = .55, SEE = 0.50 METs) predicted energy expenditure, and a cadence of 86 steps·min(-1) was equivalent to a 3-MET intensity. Although most participants were able to match cadence to prescribed music tempo, gait symmetry was not improved during the music-guided condition, compared with the self-regulated condition. CONCLUSIONS: This is the first study to investigate the utility of walking cadence for monitoring and regulating walking intensity in adults with lower limb prosthesis. Cadence has similar or superior accuracy as an indicator of walking intensity in this population, compared with the general population, and adults with a unilateral TTA are capable of walking at moderate intensity and above for meaningful bouts of time.

Stride rate and walking intensity in healthy older adults.

PURPOSE: The study investigated (a) walking intensity (stride rate and energy expenditure) under three speed instructions; (b) associations between stride rate, age, height, and walking intensity; and (c) synchronization between stride rate and music tempo during overground walking in a population of healthy older adults. METHODS: Twenty-nine participants completed 3 treadmill-walking trials and 3 overground-walking trials at 3 self-selected speeds. Treadmill VO2 was measured using indirect calorimetry. Stride rate and music tempo were recorded during overground-walking trials. RESULTS: Mean stride rate exceeded minimum thresholds for moderate to vigorous physical activity (MVPA) under slow (111.41 ± 11.93), medium (118.17 ± 11.43), and fast (123.79 ± 11.61) instructions. A multilevel model showed that stride rate, age, and height have a significant effect (p < .01) on walking intensity. CONCLUSIONS: Healthy older adults achieve MVPA with stride rates that fall below published minima for MVPA. Stride rate, age, and height are significant predictors of energy expenditure in this population. Music can be a useful way to guide walking cadence.

Evaluation of inactive adults' ability to maintain a moderate-intensity walking pace.

OBJECTIVES: To determine self-selected brisk walking pace in currently inactive adults and investigate the efficacy of rhythmic auditory stimuli to regulate moderate intensity walking. DESIGN: A single-sample controlled laboratory design. METHODS: Currently inactive adults (N=25; 76% female; age=34±13yr) completed a moderate intensity treadmill walking trial, during which cadence and steady-state O2 were measured. Participants then completed a 10-min self-paced "brisk" walk followed by a 10-min moderate-paced walk, prompted by a clip-on metronome matched to the treadmill cadence. Data were analyzed using RM t-test, Cohen's d, Bland-Altman plot, and one-way RM ANOVA. RESULTS: Mean energy expenditure and cadence during the treadmill trial were 3.88±0.53METs and 114±8stepsmin(-1). During self-paced brisk walking cadence was 124±8stepsmin(-1). Cadence during metronome-paced walking was slower for all participants (114±8stepsmin(-1); p<0.05, d=1.23). From the Bland-Altman plots, 23 participants walked within ±3stepsmin(-1) of the metronome cadence, and the other 2 participants were within ±10stepsmin(-1). There were no significant differences (p>0.05) among the minute-by-minute cadences across the 10min of either condition. CONCLUSIONS: Energy expenditure during 2.7mph treadmill walking was higher than 3 METs. Inactive adults walk at a higher cadence during "brisk" walking, compared to walking at a metronome-guided moderate pace. While the natural walking pace of inactive adults was at an intensity known to produce health benefits, and was maintained for 10min, the use of rhythmic auditory feedback is an effective method for regulating walking at a prescribed intensity in inactive adults.

Effect of maximal dynamic exercise on exhaled ethane and carbon monoxide levels in human, equine, and canine athletes.

Exercise-induced oxidative stress (EIOS) refers to a condition where the balance of free radical production and antioxidant systems is disturbed during exercise in favour of pro-oxidant free radicals. Breath ethane is a product of free radical-mediated oxidation of cell membrane lipids and is considered to be a reliable marker of oxidative stress. The heatshock protein, haem oxygenase, is induced by oxidative stress and degrades haemoglobin to bilirubin, with concurrent production of carbon monoxide (CO). The aim of this study was to investigate the effect of maximal exercise on exhaled ethane and CO in human, canine, and equine athletes. Human athletes (n = 8) performed a maximal exercise test on a treadmill, and canine (n = 12) and equine (n = 11) athletes exercised at gallop on a sand racetrack. Breath samples were taken at regular intervals during exercise in the human athletes, and immediately before and after exercise in the canine and equine athletes. Breath samples were stored in gas-impermeable bags for analysis of ethane by laser spectroscopy, and CO was measured directly using an electrochemical CO monitor. Maximal exercise was associated with significant increases in exhaled ethane in the human, equine, and canine athletes. Decreased concentrations of exhaled CO were detected after maximal exercise in the human athletes, but CO was rarely detectable in the canine and equine athletes. The ethane breath test allows non-invasive and real-time detection of oxidative stress, and this method will facilitate further investigation of the processes mediating EIOS in human and animal athletes.