The strength of time-dependent correlations known as stride interval (SI) dynamics has been proposed as an indicator of neurologically healthy gait. Most recently, it has been hypothesized that these dynamics may be necessary for gait efficiency although the supporting evidence to date is scant. The current study examines over-ground SI dynamics, and their relationship with the cost of walking and physical activity levels in neurologically healthy children aged nine to 15 years. Twenty participants completed a single experimental session consisting of three phases: 10 min resting, 15 min walking and 10 min recovery. The scaling exponent (α) was used to characterize SI dynamics while net energy cost was measured using a portable metabolic cart, and physical activity levels were determined based on a 7-day recall questionnaire. No significant linear relationships were found between a and the net energy cost measures (r < .07; p > .25) or between α and physical activity levels (r = .01, p = .62). However, there was a marked reduction in the variance of α as activity levels increased. Over-ground stride dynamics do not appear to directly reflect energy conservation of gait in neurologically healthy youth. However, the reduction in the variance of α with increasing physical activity suggests a potential exercise-moderated convergence toward a level of stride interval persistence for able-bodied youth reported in the literature. This latter finding warrants further investigation.
Denine Ellis, Ervin Sejdic, Karl Zabjek and Tom Chau
Joel T. Fuller, Clint R. Bellenger, Dominic Thewlis, John Arnold, Rebecca L. Thomson, Margarita D. Tsiros, Eileen Y. Robertson and Jonathan D. Buckley
Stride-to-stride fluctuations in running-stride interval display long-range correlations that break down in the presence of fatigue accumulated during an exhaustive run. The purpose of the study was to investigate whether long-range correlations in running-stride interval were reduced by fatigue accumulated during prolonged exposure to a high training load (functional overreaching) and were associated with decrements in performance caused by functional overreaching.
Ten trained male runners completed 7 d of light training (LT7), 14 d of heavy training (HT14) designed to induce a state of functional overreaching, and 10 d of light training (LT10) in a fixed order. Running-stride intervals and 5-km time-trial (5TT) performance were assessed after each training phase. The strength of long-range correlations in running-stride interval was assessed at 3 speeds (8, 10.5, and 13 km/h) using detrended fluctuation analysis.
Relative to performance post-LT7, time to complete the 5TT was increased after HT14 (+18 s; P < .05) and decreased after LT10 (–20 s; P = .03), but stride-interval long-range correlations remained unchanged at HT14 and LT10 (P > .50). Changes in stride-interval long-range correlations measured at a 10.5-km/h running speed were negatively associated with changes in 5TT performance (r –.46; P = .03).
Runners who were most affected by the prolonged exposure to high training load (as evidenced by greater reductions in 5TT performance) experienced the greatest reductions in stride-interval long-range correlations. Measurement of stride-interval long-range correlations may be useful for monitoring the effect of high training loads on athlete performance.
Julián Gandía, Xavier García-Massó, Adrián Marco-Ahulló and Isaac Estevan
.3200/JMBR.36.2.212-224 10.3200/JMBR.36.2.212-224 Hausdorff , J.M. ( 2007 ). Gait dynamics, fractals and falls: Finding meaning in the stride-to-stride fluctuations of human walking . Human movement science, 26 ( 4 ), 555 – 589 . PubMed ID: 17618701 doi:10.1016/j.humov.2007
Yoshifumi Kijima, Ryoji Kiyama, Masaki Sekine, Toshiyo Tamura, Toshiro Fujimoto, Tetsuo Maeda and Tadasu Ohshige
. , Paranjape , R. , Hadjistavropoulos , T. , & Barden , J.M. ( 2014 ). Evaluation of age-related differences in the stride-to-stride fluctuations, regularity and symmetry of gait using a waist-mounted tri-axial accelerometer . Gait & Posture, 39 ( 1 ), 553 – 557 . PubMed doi:10.1016/j.gaitpost.2013
Christopher K. Rhea, Jed A. Diekfuss, Jeffrey T. Fairbrother and Louisa D. Raisbeck
, fractals and falls: Finding meaning in the stride-to-stride fluctuations of human walking . Human Movement Science, 26 ( 4 ), 555 – 589 . PubMed ID: 17618701 doi:10.1016/j.humov.2007.05.003 10.1016/j.humov.2007.05.003 Hendriks , M.R. , Bleijlevens , M.H. , Van Haastregt , J. , Crebolder , H
Tsuyoshi Saida, Masayuki Kawada, Daijiro Kuroki, Yuki Nakai, Takasuke Miyazaki, Ryoji Kiyama and Yasuhiro Tsuneyoshi
, C. , Paranjape , R. , Hadjistavropoulos , T. , & Barden , J.M. ( 2014 ). Evaluation of age-related differences in the stride-to-stride fluctuations, regularity and symmetry of gait using a waist-mounted tri-axial accelerometer . Gait & Posture, 39 ( 1 ), 553 – 557 . PubMed ID: 24139685
Scott W. Ducharme and Richard E.A. van Emmerik
injury . Clinical Biomechanics, 14 , 297 – 308 . PubMed doi:10.1016/S0268-0033(98)90092-4 10.1016/S0268-0033(98)90092-4 Hausdorff , J.M. ( 2007 ). Gait dynamics, fractals and falls: Finding meaning in the stride-to-stride fluctuations of human walking . Human Movement Science, 26 , 555 – 589