Browsing by Person "Al Raisi, Lubna"

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Effects of Hybrid Custom Foot Orthoses on Running Economy, Running Mechanics and Comfort: A Double-Blinded Randomized Crossover Study
(Elsevier, 2024-10-23) Van Alsenoy, Ken K.; van der Linden, Marietta; Girard, Olivier; Ryu, Joong; Al Raisi, Lubna; Santos, Derek
Objective: This study examined the effects of orthotic materials on running economy (RE), running mechanics, and footwear comfort. Design: A double-blinded randomized crossover study design was used. Method: Eighteen athletes ran on an instrumented treadmill for six minutes at speeds corresponding to 10% below their first ventilatory threshold (average: 9.9 ± 1.3 km/h) in four footwear conditions [control (CON), Ethyl vinyl acetate (EVA), Thermoplastic Polyurethane (TPU), and a combination of EVA and TPU (HYB)]. Results: No differences were found in RE between conditions (p=0.099). All CFO materials reduced peak heel impact force vs CON (p<0.001). TPU reduced hysteresis at heel impact vs CON (-47.8%, p=0.016). Shorter flight time (-3.8%, p=0.016; -3.1%, p=0.021) and lower mean vertical loading rate (-4.0%, p=0.003; -7.1%, p<0.001) occurred for HYB vs TPU and CON, respectively. Higher peak vertical loading rates (+7.4%, p=0.002) and earlier impact peaks (-5.7%, p<0.001) were found for HYB vs TPU. HYB exhibited longer propulsive phase duration (+2.0%, p=0.003) but lower peak propulsive force (-3.3%, p=0.009) vs CON. Reduced ‘overall comfort’ (-26.4%, p=0.004), ‘comfort of heel cushioning’ (-43.3%, p<0.001), and ‘comfort of forefoot cushioning’ (-18.3%, p=0.048) was found for HYB vs TPU, but ‘comfort of forefoot cushioning’ (+48.0%, p=0.032) showed an increase vs EVA. Conclusions: Combining materials could enhance comfort during running causing subtle changes in running mechanics. Overall, neither EVA, TPU nor their combination significantly improved RE compared to CON.
Isolated and combined effects of EVA and TPU custom foot orthoses on constant speed, treadmill running kinematics
(Frontiers Media, 2023-07-07) Van Alsenoy, Ken K.; van der Linden, Marietta; Girard, Olivier; Al Raisi, Lubna; Ryu, Joong Hyun; Santos, Derek
We investigated the isolated and combined (HYB) effects of ethyl-vinyl acetate (EVA) and expanded thermoplastic polyurethane (TPU) custom foot orthoses (CFO), compared to a control condition (CON; shoes only), on constant speed, treadmill running kinematics. Twenty (10 male) well-trained runners performed four, 6-min bouts at the same individualized speed for each bout on a treadmill under four footwear conditions (EVA, TPU, HYB and CON). Twenty markers and four clusters (four markers each) were placed on lower limbs and pelvis. Lower limbs and pelvis movements were tracked using a threedimensional motion capture system with 11 cameras (Vicon MX system, Oxford, UK). Lower limb joint angles and angular velocity were normalized to 100% of the stance phase. Peak ankle eversion (P < 0.001,  2 = 0.72), peak ankle eversion angular velocity (AV) (P < 0.001,  2 = 0.64), peak ankle inversion AV (P < 0.001,  2 = 0.60), and peak ankle internal rotation AV (P < 0.001,  2 = 0.49) demonstrated the largest differences between conditions. Statistical non-parametric mapping analysis revealed that HYB exhibited the largest proportions of change during the total stance phase compared to CON. All CFO materials caused significant reductions in peak angles and peak AVs at the ankle in the frontal plane, with more pronounced effects for harder (EVA) than softer (TPU) materials. These significant reductions occurred during large portions of the total stance phase for the angles and for AVs. While some effects could be found in more proximal joints such as knee and hip, most significant effects were found at the ankle joint. Overall, combining hard EVA material in the heel and soft TPU in the forefoot (HYB) resulted in significant, more favorable changes compared to CON, that lasted for the largest proportion of stance phase when compared to wearing shoes only.
No effect of custom foot orthoses and sex on mechanical asymmetries during treadmill running
(Taylor & Francis, 2025-10-07) Van Alsenoy, Ken; Santos, Derek; van der Linden, Marietta; Ryu, Joong Hyun; Al Raisi, Lubna; Girard, Olivier
We investigated the influence of custom foot orthoses and sex on mechanical asymmetries during treadmill running. Eighteen injury-free trained individuals (9 females) ran on an instrumented treadmill for six minutes at a speed 10% below their first ventilatory threshold (average: 9.9±1.3 km/h) under four footwear conditions: original shoe liner (control), two custom orthotics (one EVA, one TPU), and a hybrid (EVA heel, TPU forefoot). Vertical and antero-posterior ground reaction forces were recorded after ~5 minutes of running, encompassing 40 steps. Mechanical asymmetry was assessed using the ‘symmetry angle’ (SA) score. There were no significant main effects for condition (all P≥0.302) or sex (P≥0.137), and no significant condition × sex interactions for any variables (P≥0.063). Mean SA scores were less than 2% for contact time (0.39±0.23%), flight time (1.90±1.35%), step frequency (0.34±0.26%), peak vertical force (1.44±1.15%), and mean vertical loading rate (1.79±1.17%). Vertical and leg stiffness had mean SA scores of 3.11±1.73% and 1.86±1.00%, respectively. For braking (1.56±0.78%) and push-off (1.54±0.81%) phases and peak braking (2.94±1.61%) and push-off (2.33±1.17%) forces, mean SA scores ranged from ~1.5% to 3.0%. Overall, both male and female runners showed relatively even strides, and custom foot orthoses did not significantly alter natural stride asymmetries.