The effects of small variations in shoe heel height on gait in people with a transtibial amputation.

BACKGROUND: Shoe heel height is considered to influence prosthetic alignment, walking comfort, and gait symmetry in people with a transtibial amputation (TTA). However, research on the effect of heel height is scarce, and no evidence is available on the effects of variations smaller than 20 mm. These small heel height variations between store-bought shoes are often overlooked by people with an amputation and may cause secondary musculoskeletal problems in the long term. OBJECTIVE: To examine the effects of small increases in heel height on gait symmetry in people with a TTA and healthy individuals. STUDY DESIGN: Experimental repeated measures study. METHODS: Fourteen participants with a TTA and 15 healthy controls were included. Pressure data, spatiotemporal data, and experienced walking comfort were measured during walking with four heel height conditions: original height and increased heights of 3, 5, and 8 mm. Symmetry in center of pressure velocity (VCOP), gait parameters, and experienced walking comfort were compared between the heel heights and between healthy controls and prosthetic walkers. RESULTS: Increased heel height resulted in a significant decrease in VCOP symmetry (P = 0.001) and experienced walking comfort (P < 0.001). The VCOP trajectory of the prosthetic leg mainly differed within the first 14.5% of the stance phase. Healthy individuals showed better VCOP symmetry in all conditions (P < 0.001). CONCLUSIONS: Healthcare professionals should advice their clients to be alert of small heel height differences between store-bought shoes, especially those larger than 5 mm. A prosthetic alignment adjustment should be considered when purchasing new shoes.

A Two-Minute Walking Test With a Smartphone App for Persons With Multiple Sclerosis: Validation Study.

BACKGROUND: Walking disturbances are a common dysfunction in persons with multiple sclerosis (MS). The 2-Minute Walking Test (2MWT) is widely used to quantify walking speed. We implemented a smartphone-based 2MWT (s2MWT) in MS sherpa, an app for persons with MS. When performing the s2MWT, users of the app are instructed to walk as fast as safely possible for 2 minutes in the open air, while the app records their movement and calculates the distance walked. OBJECTIVE: The aim of this study is to investigate the concurrent validity and test-retest reliability of the MS sherpa s2MWT. METHODS: We performed a validation study on 25 persons with relapsing-remitting MS and 79 healthy control (HC) participants. In the HC group, 21 participants were matched to the persons with MS based on age, gender, and education and these followed the same assessment schedule as the persons with MS (the HC-matched group), whereas 58 participants had a less intense assessment schedule to determine reference values (the HC-normative group). Intraclass correlation coefficients (ICCs) were determined between the distance measured by the s2MWT and the distance measured using distance markers on the pavement during these s2MWT assessments. ICCs were also determined for test-retest reliability and derived from 10 smartphone tests per study participant, with 3 days in between each test. We interviewed 7 study participants with MS regarding their experiences with the s2MWT. RESULTS: In total, 755 s2MWTs were completed. The adherence rate for the persons with MS and the participants in the HC-matched group was 92.4% (425/460). The calculated distance walked on the s2MWT was, on average, 8.43 m or 5% (SD 18.9 m or 11%) higher than the distance measured using distance markers (n=43). An ICC of 0.817 was found for the concurrent validity of the s2MWT in the combined analysis of persons with MS and HC participants. Average ICCs of 9 test-retest reliability analyses of the s2MWT for persons with MS and the participants in the HC-matched group were 0.648 (SD 0.150) and 0.600 (SD 0.090), respectively, whereas the average ICC of 2 test-retest reliability analyses of the s2MWT for the participants in the HC-normative group was 0.700 (SD 0.029). The interviewed study participants found the s2MWT easy to perform, but they also expressed that the test results can be confronting and that a pressure to reach a certain distance can be experienced. CONCLUSIONS: The high correlation between s2MWT distance and the conventional 2MWT distance indicates a good concurrent validity. Similarly, high correlations underpin a good test-retest reliability of the s2MWT. We conclude that the s2MWT can be used to measure the distance that the persons with MS walk in 2 minutes outdoors near their home, from which both clinical studies and clinical practice can benefit.

Maximal Walking Distance in Persons with a Lower Limb Amputation.

The distance one can walk at a time could be considered an important functional outcome in people with a lower limb amputation. In clinical practice, walking distance in daily life is based on self-report (SIGAM mobility grade (Special Interest Group in Amputee Medicine)), which is known to overestimate physical activity. The aim of this study was to assess the number of consecutive steps and walking bouts in persons with a lower limb amputation, using an accelerometer sensor. The number of consecutive steps was related to their SIGAM mobility grade and to the consecutive steps of age-matched controls in daily life. Twenty subjects with a lower limb amputation and ten age-matched controls participated in the experiment for two consecutive days, in their own environment. Maximal number of consecutive steps and walking bouts were obtained by two accelerometers in the left and right trouser pocket, and one accelerometer on the sternum. In addition, the SIGAM mobility grade was determined and the 10 m walking test (10 MWT) was performed. The maximal number of consecutive steps and walking bouts were significantly smaller in persons with a lower limb amputation, compared to the control group (p < 0.001). Only 4 of the 20 persons with a lower limb amputation had a maximal number of consecutive steps in the range of the control group. Although the maximal covered distance was moderately correlated with the SIGAM mobility grade in participants with an amputation (r = 0.61), for 6 of them, the SIGAM mobility grade did not match with the maximal covered distance. The current study indicated that mobility was highly affected in most persons with an amputation and that the SIGAM mobility grade did not reflect what persons with a lower limb amputation actually do in daily life. Therefore, objective assessment of the maximal number of consecutive steps of maximal covered distance is recommended for clinical treatment.