Author(s): REY, O., NICOL, C., PENALBA, T., DE GRAAF, J.B., MESURE, S., Institution: AIX-MARSEILLE UNIVERSITY, Country: FRANCE, Abstract-ID: 2565

INTRODUCTION:
Functional walking capacity is a major factor in health and physical performance. The Six-Minute Walk Test (6MWT) [1] and the Incremental Shuttle Walk Test (ISWT) [2] are widely used, but they have methodological limitations. The self-paced 6MWT may limit physiological standardisation [1], while the repeated 180° turns in the ISWT increase braking–acceleration phases, mechanical stress, and gait variability [3]. These constraints may be exacerbated in overweight individuals, whose locomotor pattern is altered both mechanically and energetically [4]. Furthermore, using visual cues reduces stride length and variability, while significantly increasing walking speed [5].
An incremental Square Test (ST) with beveled corners was developed to reduce directional constraints while maintaining speed progression. This study aimed to: (i) validate ST against 6MWT and ISWT; (ii) assess the effect of visual light guidance on gait regulation; and (iii) evaluate its suitability under simulated overweight.
METHODS:
Eighteen normal-weight young men and women (20.7 ± 2 years; BMI 22.7 ± 2.8 kg·m⁻²) completed five randomised sessions: 6MWT, ISWT, and three ST conditions - without light guidance (ST1), with light guidance (ST2), and with light guidance plus a 20% body-mass load (ST3). Speed increments matched those of ISWT (+0.5 km·h⁻¹·min⁻¹). Heart rate (HR), peak speed, perceived exertion, and step kinetics were recorded using HR monitors and instrumented insoles (Loadsol, 100 Hz). Repeated-measures ANOVA, Pearson correlations, intraclass correlation coefficients (ICC) and Bland–Altman analyses assessed validity and reliability.
RESULTS:
Peak speed was higher in ST1 and ST2 than ISWT (respectively +14,21 and + 15,31 %, p < .001). Despite comparable peak ground reaction forces, ISWT induced earlier increases in gait variability and higher HR values. Light guidance reduced gait-cycle variability and decreased mean HR by 7% in ST2 versus ST1 (p < .01), without affecting peak performance.
Under simulated overweight (ST3), higher peak speed was reached than in ISWT (+8%, p < .001) with similar peak HR. Although mechanical load increased, locomotor variability remained also lower than in ISWT. Correlations between repeated ST and ISWT ranged from moderate to high (r = 0.55–0.87), with moderate reliability (ICC ≈ 0.6).
CONCLUSION:
The Square Test demonstrated construct validity and reproducibility for functional walking assessment. By reducing braking constraints, the ST protocol improved locomotor stability and economy compared with ISWT, particularly under light guidance. The ST protocol appears to be suitable for evaluating walking performance and assessing the associated cardiovascular function in populations including individuals with overweight.
[1] Bruyneel et al., 2012 [2] Singh et al., 1992 [3] Almodhy et al., 2014 [4] Browning & Kram, 2005 [5] Nishikawa et al., 2023.