Publication Date

2016-11-09

Availability

Open access

Embargo Period

2016-11-09

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PHD)

Department

Kinesiology and Sport Sciences (Education)

Date of Defense

2016-10-26

First Committee Member

Joseph F. Signorile

Second Committee Member

Moataz Eltoukhy

Third Committee Member

Christopher Kuenze

Fourth Committee Member

Michael G. Baraga

Abstract

Background: The recent trend in running entails changing from landing on the heels (RFS) to landing on the midfoot (MFS) or forefoot (FFS). This initiative is based on evidence showing a direct relationship between lower limb running-related injuries and heel-striking. Changing from RFS to MFS requires shortening the stride cycle. Studies exist showing biomechanical, neuromuscular, and physiological changes produced by shifting from RFS to MFS. These results are predominantly based on acute verbal instruction, provided either on a treadmill or overground, but we could find no controlled study comparing changes due to training in treadmill and overground running, or at submaximal and maximal speeds. Additionally, no study has quantified the impact of a resistive proprioceptive device coupled with training on changes in running style. Objective: The purpose of this study was to examine the effectiveness of using a proprioceptive resistive device (EZRB) in concert with 6 weeks of Pose Method run training (PMRT) to convert RFS recreational runners to MFS by quantifying changes biomechanical, electromyographical (EMG) and physiological changes across different speeds and terrains. Methods: Nineteen recreational runners were randomly assigned to one of three groups Controls (C: 4M, 1F, h = 1.78±0.1 m, mass= 78.6±14 kg, age = 51±5.5 y), drills only (DO: 3M, 4F, h= 1.70±0.1 m, mass= 67.3 ±12 kg, age = 48±9.6 years), and drills plus belt (DB: 6M, 1F, h= 1.79±0.1 m, mass= 80±9.5 kg, age= 47±12 years). Subjects completed a maximum oxygen uptake (VO2MAX) test on the initial testing day. On two subsequent days, they performed a submaximal test on treadmill, and submaximal and maximal tests on a 2 x 200 m measured overground course. After six weeks of training they repeated the 3-day test battery. Cardiopulmonary ergometry was used to collect cardiovascular measures (VO2MAX, RER, HR) and oxygen cost (COST) and HR at lactate threshold (HRLT) were computed. Kinovea video analysis was used to measure knee flexion (KFA) and dorsiflexion (DFA) angles, insoles were used to measure ground contact for cadence and stride length (CAD, SL), surface EMG was used to quantify use of the right leg rectus femoris (RF), vastus lateralis (VL), biceps femoris (BF), semitendinosus (ST), and lateral gastrocnemius (LG), and a timing system was used to determine performance time (TP) during overground trials. Mixed-design ANOVAs were conducted to determine differences across the training period and between groups. Results: A significant difference in gait shift from RFS to MFS was observed between the C and treatment groups. On the treadmill both intervention groups increased CADTM85 (DO(p=.003), DB(p=.039) and decreased DFATM85 (DO (p=.039), DB (p=.029)); while overground DO decreased REROUT85 (p=.039), REROUTMAX (p=.025), DFAOUT85 (p=.019) and DFAOUTMAX (p=.013). DO also increased RFTM85 activity, while DB decreased in this variable enough to significantly differentiate DB from other groups (p=.042). Within group changes for C included an increase HRLT (p=.028), and REROUT85 (p=.011); for DO a decrease in TPOUT85 (p=.045), KFAOUT85 (p=.001), DFATM85 (p=.001), DFAOUT85 (p=<.001), and increases in RFOUT85 (p=.045), BFOUT85 (p=.008), STTM85 (p=.004), and CADOUT85 (p=.025); and, for DB an increase in BFTM85 (p=.008), BFOUTMAX (p=.003), STTM85 (p=.007), STOUTMAX (p=.015), CADOUTMAX (p<.001), and decreases in KFAOUTMAX (p=<.001) and DFAOUTMAX (p=.003). Conclusion: Changes in biomechanics, cardiovascular responses, timed performance and muscle activations observed in the DO and DB at the different run conditions indicate a significant shift from RFS to MFS after 6 weeks of PMRT instruction, unique effectiveness of the proprioceptive device could not be established, but differences warrant further investigation.

Keywords

Foot strike pattern; biomechanics; running styles; recreational runners; Pose Method; EMG foot strike patterns

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