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|Title:||Investigation of running shoe design on the foot kinematics, kinetics, and muscle recruitment pattern in people with overpronation problem||Authors:||Cheung, Tsz-hei Roy||Degree:||Ph.D.||Issue Date:||2010||Abstract:||Motion control footwear is a common technology in running shoe designs. The function of motion control footwear is mainly to reduce excessive rearfoot pronation in runners for injury prevention. Because erratic rearfoot kinematics may affect proximal joints by the linkage of human kinetic chain, the functions of motion control footwear may not only be confined to kinematic control. The functions of motion control footwear are not well explored and understood. Thus, the overall purpose of this thesis is to explore functions of motion control footwear in runners with excessive rearfoot pronation. Experiments were conducted to test the efficacy of motion control footwear in terms of 1) rearfoot kinematics control; 2) plantar loading control; and 3) lower extremity muscle activity control. These parameters were also tested after muscle fatigue because runners are more prone to injury in such status. A total of forty eight female runners were recruited. Three of them were rejected due to their normal rearfoot pronation. All the subjects were provided standard motion control footwear and neutral footwear for treadmill running sessions with 1-week apart. Motion capture analysis suggested that the maximum rearfoot pronation of runners was reduced in motion control footwear condition, compared with neutral footwear condition (p <0.001; 10.58° with motion control footwear, 13.94° with neutral footwear). After 1500m run, while the rearfoot supinators were fatigued (p <0.01), the maximum rearfoot pronation further increased when runners put on neutral footwear (p <0.01; 6.5° 95% C.I. 4.7-8.2°) but not in motion control footwear condition (p =0.06; 0.7° 95% C.I. -0.3-1.4°). Subjectively, runners were not able to differentiate the kinematics control function between two test footwear model, indicated by feedback score (p =0.711) in a validated questionnaire. These results highlighted the importance of rearfoot posture assessment by medical professionals, rather than self adjustment by runners. Plantar loading sensors revealed that the medial foot structures sustained higher loading (p =0.001; 364 to 418 N; 15% increase at medial midfoot) with neutral footwear condition after muscle fatigue caused by running 1500m. This increased loading pattern is highly associated with various running injuries. On the other hand, the plantar loading was similar in motion control footwear condition (p =0.572). Electromyography indicated that the muscle activity of tibialis anterior (TA) and peroneus longus (PL) increased with mileage during 10km run. The activation of both TA (p <0.001; normalized RMS 10.5% higher) and PL (p <0.001; normalized RMS 9.6% higher) was higher in neutral footwear condition than motion control footwear condition. Also, significantly higher amount of muscle fatigue was noted in PL during the neutral footwear testing condition (p <0.001; median frequency drop in motion control footwear = 2.10 Hz; median frequency drop in neutral footwear = 11.60 Hz).
In quadriceps muscles, the experiments showed that the amplitude of median frequency (MF) drop in vastus medialis oblique (VMO) was higher in the neutral footwear condition (p=0.008; median frequency drop in motion control footwear = 1.23 Hz; median frequency drop in neutral footwear = 9.51 Hz) while the vastus lateralis (VL) had a more significant drop in MF when running with motion control footwear (p=0.001; median frequency drop in motion control footwear = 3.80 Hz; median frequency drop in neutral footwear = 1.78 Hz). Early fatigue of the major patella stabilizing muscle VMO, which occurred in neutral footwear condition, may lead to patellofemoral pain syndrome in runners. The onset timing of VMO and VL was significant different with footwear condition change and mileage (p=0.001). Numerically, the VMO of the subjects activated at around 5.3% of a duty cycle earlier than VL when running with motion control footwear; whereas for the neutral footwear running condition, there was a delay in VMO activation by about 4.6% of a duty cycle compared to VL. The onset delay time of VMO was strongly correlated (r = 0.948; p < 0.001) with the running mileage in neutral footwear condition only. In the motion control footwear condition, this correlation was very weak (r = 0.258; p =0.472). The results of electromyography experiments suggested motion control footwear provided favorable running conditions in terms of higher resistance towards muscle fatigue, more stable activation of shank stabilizing muscles, as well as enhanced temporal activation of patella stabilizers. These footwear functions may be able to reinforce injury prevention in running population. The findings of this thesis form a basis for the establishment of a running injury prevention program or adjunct therapy intervention by appropriate footwear prescription in runners with excessive rearfoot pronation problem.
|Subjects:||Hong Kong Polytechnic University -- Dissertations
Running shoes -- Health aspects.
Running -- Physiological aspects
Foot -- Wounds and injuries -- Prevention.
|Pages:||xix, 191 leaves : ill. (some col.) ; 30 cm.|
|Appears in Collections:||Thesis|
View full-text via https://theses.lib.polyu.edu.hk/handle/200/5538
Citations as of Sep 17, 2023
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