The Effects of Local Muscle Fatigue on Shock Attenuation Characteristics During Running

Links

Abstract

The purpose of this study was to examine shock attenuation (SA) characteristics as well as stride characteristics before and after a fatigue protocol of the ankle dorsiflexors while running on a treadmill. Thirteen females (25.4 ± 3.8 yrs; 63.2 ± 8.9 kg; 164.3 ± 3.1 cm) ran at the same (preferred) speed prior to and following bilateral local muscle fatigue of the ankle dorsiflexors. The fatigue protocol consisted of five sets of maximal concentric and eccentric contractions with a 15-second rest between the sets. Accelerometers (1004 Hz) were securely mounted on the distal aspect of the tibia and on the forehead. Head impact acceleration (ahead) and leg impact acceleration (aieg) over 10 consecutive strides per subject-condition were selected and used to quantify SA. Paired Mests were used to compare each dependent variable (SA, ahead, aieg, stride frequency, stride length) between conditions (running before vs. after the fatigue protocol). Results indicated SA was 4.2% greater when running after the fatigue protocol [78.4 ±6.1 % (mean ± std)] than when running before the fatigue protocol (74.2 ± 6.6 %; p < .05). Additionally, aieg was, on average, 1.7 g greater during running after (6.0 ± 2.4 g) than before (4.3 ± 1.6 g) the fatigue protocol (p < .05). ahead exhibited no significant difference before and after the fatigue protocol. Furthermore, stride frequency was 1.4% greater when running after the fatigue protocol (p < .05). There was no statistical difference in stride length (p = .053). These results indicate that SA and aieg were sensitive to local muscle fatigue, with more shock being attenuated through body along with increased aieg during fatigued running. The increased a^g and SA suggest that local muscle fatigue contributes to the incapability of the musculoskeletal system to maintain the impaet acceleration at the leg segment level; however, runners’ systems may have adjusted to compensate for local fatigue. Therefore, the ankle dorsiflexors may play a role in the development of running related injuries.

Cited Works (10)

Year	Entry
1992	Perry J. Gait Analysis: Normal and Pathological Function. Thorofare, NJ: SLACK Incorporated; 1992.
1980	Cavanagh PR, Lafortune MA. Ground reaction forces in distance running. J Biomech. 1980;13(5):397-406.
1986	Nigg BM, ed. Biomechanics of Running Shoes. Champaign, IL: Inc., Human Kinetics Publishers; 1986.
2002	Taunton JE, Ryan MB, Clement DB, McKenzie DC, Lloyd-Smith DR, Zumbo BD. A retrospective case-control analysis of 2002 running injuries. Br J Sports Med. April 2002;36(2):95-101.
2000	Hreljac A, Marshall RN, Hume PA. Evaluation of lower extremity overuse injury potential in runners. Med Sci Sports Exer. September 2000;32(9):1635-1641.
1992	van Mechelen W, Hlobil H, Kemper HCG. Incidence, severity, aetiology and prevention of sports injuries: a review of concepts. Sports Med. August 1992;14(2):82-99.
1999	Mercer JA. Effects of Fatigue on Shock Attenuation During Running [PhD thesis]. Eugene, OR: University of Oregon; June 1999.
1995	Gerritsen KGM, van den Bogert AJ, Nigg BM. Direct dynamics simulation of the impact phase in heel-toe running. J Biomech. June 1995;28(6):661-668.
1979	McMahon TA, Greene PR. The influence of track compliance on running. J Biomech. 1979;12(12):893-904.
1978	James SL, Bates BT, Osternig LR. Injuries to runners. Am J Sports Med. 1978;6(2):40-50.

Cited By (1)

Year	Entry
2010	Liebenberg JN. Kinetics At Front Foot Contact of Cricket Bowling During a 10-Over Bowling Spell [Master's thesis]. Las Vegas, University of Nevada; May 2010.