Changes in tendon stiffness and running economy in highly trained distance runners (original) (raw)
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Energy cost of running and Achilles tendon stiffness in man and woman trained runners
Physiological Reports, 2013
The energy cost of running (E run ), a key determinant of distance running performance, is influenced by several factors. Although it is important to express E run as energy cost, no study has used this approach to compare similarly trained men and women. Furthermore, the relationship between Achilles tendon (AT) stiffness and E run has not been compared between men and women. Therefore, our purpose was to determine if sex-specific differences in E run and/or AT stiffness existed. E run (kcal kg À1 km À1 ) was determined by indirect calorimetry at 75%, 85%, and 95% of the speed at lactate threshold (sLT) on 11 man (mean AE SEM, 35 AE 1 years, 177 AE 1 cm, 78 AE 1 kg, _ VO 2 max = 56 AE 1 mL kg À1 min À1 ) and 18 woman (33 AE 1 years, 165 AE 1 cm, 58 AE 1 kg, _ VO 2 max = 50 AE 0.3 mL kg À1 min À1 ) runners. AT stiffness was measured using ultrasound with dynamometry. Man E run was 1.01 AE 0.06, 1.04 AE 0.07, and 1.07 AE 0.07 kcal kg À1 km À1 . Woman E run was 1.05 AE 0.10, 1.07 AE 0.09, and 1.09 AE 0.10 kcal kg À1 km À1 . There was no significant sex effect for E run or RER, but both increased with speed (P < 0.01) expressed relative to sLT. High-range AT stiffness was 191 AE 5.1 N mm À1 for men and 125 AE 5.5 N mm À1 , for women (P < 0.001). The relationship between low-range AT stiffness and E run was significant at all measured speeds for women (r 2 = 0.198, P < 0.05), but not for the men. These results indicate that when E run is measured at the same relative intensity, there are no sex-specific differences in E run or substrate use. Furthermore, differences in E run cannot be explained solely by differences in AT stiffness.
European Journal of Applied Physiology, 2013
Exercise-induced changes in triceps surae tendon stiffness and muscle strength affect running economy in humans Kirsten Albracht & Adamantios Arampatzis 1 2 3 Your article is protected by copyright and all rights are held exclusively by Springer-Verlag Berlin Heidelberg. This e-offprint is for personal use only and shall not be selfarchived in electronic repositories. If you wish to self-archive your article, please use the accepted manuscript version for posting on your own website. You may further deposit the accepted manuscript version in any repository, provided it is only made publicly available 12 months after official publication or later and provided acknowledgement is given to the original source of publication and a link is inserted to the published article on Springer's website. The link must be accompanied by the following text: "The final publication is available at link.springer.com".
Journal of Functional Morphology and Kinesiology
Introduction: The kinesiotape (KT) method is used to exert a positive effect on muscular, nervous, and organ systems, recognizing the importance of muscle movement. It is widely applied in runners for performance enhancement. However, there is no scientific background to use it as a running speed modulator. Objectives: The purpose of this study was to verify the KT effect on running performance in university-level students while speed is considered. The 1 km run and 40 m shuttle run were investigated. Participants were highly motivated to run as fast as possible since the research was part of the graded fitness test. Students wanted to perform as well as possible to get good marks. Methods: A total of 150 students aged 19.93 ± 0.85 with BMIs of 26.93 ± 0.98 were randomly distributed to the experimental (EG), placebo (PG), and control group (CG). In the EG, 50 students were measured pre-test (no KT) and post-test (KT applied). In the PG, 50 students were measured the same way using t...
Achilles tendon stiffness is unchanged one hour after a marathon
Journal of Experimental Biology, 2012
AT stiffness was tested on three occasions: (1) 2-4days before the race (2days pre-race), (2) 2h before the race (2h pre-race) and (3) SUMMARY Overuse-induced injuries have been proposed as a predisposing factor for Achilles tendon (AT) ruptures. If tendons can be overloaded, their mechanical properties should change during exercise. Because there data are lacking on the effects of a single bout of long-lasting exercise on AT mechanical properties, the present study measured AT stiffness before and after a marathon. AT stiffness was determined as the slope of the force-elongation curve between 10 and 80% of maximum voluntary force. AT force-elongation characteristics were measured in an ankle dynamometer using simultaneous motion-capture-assisted ultrasonography. Oxygen consumption and ankle kinematics were also measured on a treadmill at the marathon pace. All measurements were performed before and after the marathon. AT stiffness did not change significantly from the pre-race value of 197±62Nmm-1 (mean ± s.d.) to the post-race value of 206±59Nmm-1 (N12, P0.312). Oxygen consumption increased after the race by 7±10% (P<0.05) and ankle kinematic data revealed that in nine out of 12 subjects, the marathon induced a change in their foot strike technique. The AT of the physically active individuals seems to be able to resist mechanical changes under physiological stress. We therefore suggest that natural loading, like in running, may not overstress the AT or predispose it to injury. In addition, decreased running economy, as well as altered foot strike technique, was probably attributable to muscle fatigue.
European Journal of Applied Physiology, 2014
shortening amplitudes (p < 0.01) of the tendinous tissue of medial gastrocnemius (MG), but greater tendon contribution to the muscle-tendon unit shortening (p < 0.05). The MG fascicles of the Kenyans were shorter not only at the resting standing position, but also during the contact phase at both running speeds (p < 0.01). The EMG profiles of the Kenyans showed lower braking/preactivation ratio in both MG and tibialis anterior (p < 0.05) muscles. They were also characterized by negative relationships between the Achilles tendon moment arm and the MG fascicle shortening during contact (r = −0.54, p < 0.01). In contrast, the Japanese presented the classical stretch-shortening cycle muscle activation profile of relatively high MG EMG activity during the braking phase. Conclusion These findings provide new suggestions that the Kenyans have unique structural characteristics which can result in the reduction of muscle and tendinous stretchshortening loading together with smaller muscle activation during contact at submaximal running speed.
2021
Purpose: This study aimed to determine whether triceps surae’s muscle architecture and Achilles tendon parameters are related to running metabolic cost (C) in trained long-distance runners. Methods: Seventeen trained male recreational long-distance runners (mean age = 34 years) participated in this study. C was measured during submaximal steady-state running (5 min) at 12 and 16 km h–1 on a treadmill. Ultrasound was used to determine the gastrocnemius medialis (GM), gastrocnemius lateralis (GL), and soleus (SO) muscle architecture, including fascicle length (FL) and pennation angle (PA), and the Achilles tendon cross-sectional area (CSA), resting length and elongation as a function of plantar flexion torque during maximal voluntary plantar flexion. Achilles tendon mechanical (force, elongation, and stiffness) and material (stress, strain, and Young’s modulus) properties were determined. Stepwise multiple linear regressions were used to determine the relationship between independent ...
European Journal of Applied Physiology, 2001
In cycle exercise, it has been suggested that critical power, maximal lactate steady state, and lactate turnpoint all demarcate the transition between the heavy exercise domain (in which blood lactate is elevated above resting values but remains stable over time) and the very heavy exercise domain (in which blood lactate increases continuously throughout constant-intensity exercise). The purpose of the present study was to assess the level of agreement between critical velocity (CV), maximal lactate steady-state velocity (MLSSV), and lactate turnpoint velocity (LTPV) during treadmill running. Eight male subjects [mean (SD) age 28 (5) years, body mass 71.2 (8.0) kg, maximum oxygen uptake 54.9 (3.2) mlákg ±1 ámin ±1 ) performed an incremental treadmill test for the determination of LTPV (de®ned as a sudden and sustained increase in blood lactate concentration ([La]) at @2.0±5.0 mM). The subjects returned to the laboratory on eight or nine occasions for the determination of CV and MLSSV. The CV was determined from four treadmill runs at velocities that were chosen to result in exhaustion within 2±12 min. The MLSSV was determined from four or ®ve treadmill runs of up to 30 min duration and de®ned as the highest velocity at which blood [La] increased by no more than 1.0 mM after between 10 and 30 min of exercise. Analysis of variance revealed no signi®cant dierences between [mean (SD)] CV [14.4 (1.1) kmáh ±1 ], MLSSV [13.8 (1.1) kmáh ±1 ] and LTPV [13.7 (0.6) kmáh ±1 ]. However, the bias 95% limits of agreement for comparisons between CV and MLSSV [0.6 (2.2) kmáh ±1 ], CV and LTPV [0.7 (2.7) kmáh ±1 ], and MLSSV and LTPV [0.1 (1.8) kmáh ±1 ] suggest that the extent of disagreement is too great to allow one variable to be estimated accurately from another in individual subjects. Direct determination of MLSSV is necessary if precision is required in experimental studies.
Changes in Running Kinematics and Kinetics Following a 10 km Run
International Journal of Sports Physical Therapy
Background Little is known about changes in kinetics or kinematics following a 10 km training run. This information has implications on risk of running-related injury. Purpose The purpose of this study was to examine the effect of a 10 km run on running kinematics and kinetics in a sample of experienced runners. Study Design Cross-Sectional Study Subjects Nineteen runners ages 18-48 (7 female, 12 male) consented to participate including eight (3 female, 5 male) ultra-runners, and 11 (4 female, 7 male) recreational runners. Methods Following collection of demographic data and completion of a short running survey, participants did a 6-minute run at their self-selected running speed to acclimate to the instrumented treadmill. Reflective markers were placed over designated anatomical landmarks on both sides of the pelvis as well as the left lower extremity and marked with a skin pen. Subjects then ran on the treadmill and 30 seconds of video data were recorded at 240 frames/sec using a ...
Kinematic alterations after two high-intensity intermittent training protocols in endurance runners
Journal of Sport and Health Science, 2016
Purpose: This study aimed to evaluate running kinematic characteristics during the early and late stages of 2 high-intensity intermittent training (HIIT) protocols with similar external load but different average running pace, as well as to compare the fatigue-induced changes during both HIIT protocols at a kinematic level. Methods: Eighteen endurance runners were tested on a track on 2 occasions: 10 runs of 400 m with 90À120 s recovery between running bouts (10 £ 400 m), and 40 runs of 100 m with 25À30 s recovery between running bouts (40 £ 100 m). Heart rate was monitored during both protocols; blood lactate accumulation and rate of perceived exertion were recorded after both exercises. A high-speed camera was used to measure sagittalplane kinematics at the first and last runs during both HIIT protocols. The dependent variables were spatial-temporal parameters (step length and contact and flight time), joint angles during support (relative angles of the hip, knee, and ankle), and foot strike pattern. Results: High levels of exhaustion were reached by the athletes during both workouts (blood lactate accumulation >12 mmol/L, rate of perceived exertion >15; peak heart rate (HR peak) > 176 bpm). A within-protocol paired t test (first vs. last run) revealed no significant changes (p 0.05) in kinematic variables during any of the HIIT sessions. A between-protocol comparison with the first run of each protocol revealed the effect of running speed on kinematics: +2.44 km/h during the 40 £ 100 m: shorter contact and flight time (p 0.01) and longer step length (p = 0.001); greater hip flexion (p = 0.031) and ankle extension (p = 0.001) at initial contact; smaller knee and ankle flexion (p < 0.001) at midstance; and greater hip extension at toe-off (p < 0.001). Conclusion: HIIT sessions including runs for 15À90 s and performed at intensity above the velocity associated with maximal oxygen uptake did not consistently perturb the running kinematics of trained endurance runners.