Using digital music technology to promote healthy walking in adults with unilateral trans-tibial amputation David Rowe1, David McMinn2, Leslie Peacock1, Arjan Buis3, Rona Sutherland1, Emma Henderson3, Allan Hewitt1 1Physical Activity for Health Research Group, University of Strathclyde, Glasgow, Scotland; 2Rowett Institute, University of Aberdeen, Scotland; 3National Centre for Prosthetics and Orthotics, University of Strathclyde, Glasgow, Scotland Methods Following a treadmill familiarization trial, 17 participants (88% male; age=52±13 yr; height=1.66±0.16 m; weight=85.0±20.2 kg; BMI=31.5±9.6 kg/m2; 1-25 yr post-amputation) completed two treadmill walking trials, during which steady-state VO2 was measured. They then completed two overground walking trials of at least 5 min. The first trial was self-paced following instructions to “walk briskly”. The second trial was paced using a digital music track which was individually determined from the treadmill trials to be at a moderate cadence (≈3MET). Speed, cadence and various gait measures were obtained via time and distance, hand-counting, and a GaitRite mat, respectively. Gait symmetry was calculated using the standardized symmetry index (SI) of Mattes, Martin, and Royer.10 Data were analyzed using RM t-test, Cohen’s d, and Bland-Altman plot. Background Individuals with amputation have reduced life expectancy1 and adults with transtibial amputation (TTAs) are generally less active than non-amputees,2,3 particularly vascular TTAs (where amputation was the result of vascular disease associated with conditions such as diabetes or atherosclerosis).3,4 Health benefits result primarily from physical activity of at least moderate intensity,5,6 which equates to activity performed at or above a threshold of 3 METs (i.e., 3 times the resting rate of energy expenditure). Observations of walking speeds under natural free living conditions indicate that walking speed varies, sometimes being above speeds equivalent to moderate intensity,7,8 but in other individuals being slower than a moderate speed.9 These studies focused on healthy, habitual walkers and it is unclear whether their findings apply to inactive adults or clinical populations. A few studies have investigated walking pace of lower-limb amputees during short (10-60 meters) walk tests, but very limited evidence is available on typical walking pace or the ability to match walking cadence (step rate) to the beat of auditory stimuli (e.g., metronome or music) in this population, over longer distances. Table 1. Descriptive statistics for treadmill (TM) and overground (OG) walking trials (n = 17) Variable Mean SD Min Max TM energy expenditure (METs) 3.33 0.74 2.31 4.84 TM speed (mph) 1.83 0.67 0.80 3.00 TM cadence (steps/min) 97.29 19.50 50 120 TM heart rate (b/min) 109.52 10.97 91 131 TM RPE 11.82 1.80 7 15 OG speed (brisk) (mph) 2.78 0.59 1.43 3.73 OG cadence (brisk) (steps/min) 113.21 13.48 88 139 OG heart rate (brisk) (b/min) 117.66 13.75 96 143 OG RPE (brisk) 13.12 1.32 11 OG speed (music-guided) (mph) 2.55 0.65 1.17 3.58 OG cadence (music-guided) (steps/min) 104.03 13.16 80 122 OG heart rate (music-guided) (b/min) 113.63 10.55 93 128 OG RPE (music-guided) 12.76 2.93 6 17 Results Results of the treadmill and overground trials are presented in Table 1. From the treadmill trials, the relationship between cadence and METs was strong (R2 = .65 and SEE = 0.45 METs), and a cadence of 86 steps/min corresponded to moderate intensity (3 METs). During the self-selected brisk overground walking trial, participants walked at a cadence and speed that were significantly (p < .001) faster than during the music-paced walking trial. Effect sizes were medium to large for cadence and speed (d = 0.69 and 0.38, respectively). From the Bland-Altman plot (see Figure 1), 12 of 17 (71%) participants walked within 10 steps/min of the prescribed cadence (music tempo). No participants walked slower than the prescribed cadence. From discussions with the participants, the more extreme discrepancies were most likely due to a reluctance to comply with what seemed to the participants to be relatively slow tempos, rather than an inability to match the cadence. Gait symmetry was not significantly different (p > .05) between self-selected and music-guided overground walking for step time, step length, or single stance time. i Purpose To (a) compare walking speed and cadence during self-regulated “brisk” overground walking and music-guided walking; (b) determine ability to match step rate to a prescribed cadence prompt administered via a portable digital music player; and (c) investigate differences in gait symmetry between self-regulated walking and music-guided walking. Conclusions/Discussion Non-traumatic trans-tibial amputees walk faster during self-selected “brisk” walking than during music-guided moderate intensity walking. Additionally, they are able to match a prescribed cadence by following an auditory stimulus relatively well. The use of auditory stimuli is therefore an effective way to prompt walking of a health-enhancing pace in this population, and they appear to be quite capable of walking above moderate intensity. Using music tempo to guide walking cadence does not appear to improve gait symmetry in the short-term, which may be due to this population not being affected by neuromotor conditions such as stroke and Parkinsons. Fig 1. Bland-Altman Plot of Music-Guided Cadence References Bo Ebskov L. Dysvascular amputations and long-term survival in a 20-year follow-up study. Int J Rehabil Res. 2006;29:325-328. Bussmann JB, Schrauwen HJ, Stam HJ. Daily physical activity and heart rate response in people with a unilateral traumatic transtibial amputation. Arch Phys Med Rehabil. 2008;89:430-434. van den Berg-Emons RJ, Bussmann JB, Stam HJ. Accelerometry-based activity spectrum in persons with chronic physical conditions. Arch Phys Med Rehabil. 2010;91:1856-1861 Bussmann JB, Grootscholten EA, Stam HJ. Daily physical activity and heart rate response in people with a unilateral transtibial amputation for vascular disease. Arch Phys Med Rehabil. 2004;85:240-244. 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Walking symmetry and energy cost in persons with unilateral transtibial amputations: Matching prosthetic and intact limb inertial properties. Arch Phys Med Rehabil. 2000;81:561-568. Contact details: david.rowe@strath.ac.uk