Impact Attenuation and Variability during Running in Females: A Lifespan Investigation

Dufek, Janet S.; Mercer, John A.; Teramoto, Kaori; Mangus, Brent C.; Freedman, Julia A.

doi:10.1123/jsr.17.3.230

Cited by 12 publications

(13 citation statements)

References 21 publications

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“…13,15,17,18 In our study, the magnitude of shock attenuation tended to be lower for child runners (about 66%-76%) compared with published adult running data despite LgPk (3.3-10.5g) and HdPk (0.9-2.0g) ranges that were comparable with adult running data. 13,15,17,18 These results are similar to those for child runners 21 (n 5 11 girls, 9.2 6 1.9 years) who exhibited peak impact accelerations from about 4.9 to 6.1g at the leg and from 1.2 to 1.4g at the head level. Comparing the results to those of adults is complicated, because the variability of impact accelerations may be greater for children than adults 21 and because shock attenuation and LgPk are influenced by a variety of factors, including the primary factors of running speed and SL.…”

Section: Discussionsupporting

confidence: 78%

“…13,15,17,18 These results are similar to those for child runners 21 (n 5 11 girls, 9.2 6 1.9 years) who exhibited peak impact accelerations from about 4.9 to 6.1g at the leg and from 1.2 to 1.4g at the head level. Comparing the results to those of adults is complicated, because the variability of impact accelerations may be greater for children than adults 21 and because shock attenuation and LgPk are influenced by a variety of factors, including the primary factors of running speed and SL. 13,17 Our participants ran at preferred speeds ranging from 1.76 to 3.20 m/s and used SLs ranging from 1.0 to 2.1 m/stride.…”

Section: Discussionsupporting

confidence: 78%

“…We are not aware of any shock attenuation data for children running in the literature with which to compare our results; Dufek et al 21 reported LgPk and HdPk for girls running but did not report on shock attenuation. However, the body of research on shock attenuation for adults running is robust and growing.…”

Section: Discussionmentioning

confidence: 96%

“…Although our shock attenuation data for children seem to have lower values than data for adults, it is not clear if this is simply a result of slower speed or if differences exist in mechanisms for attenuating shock between children and adults. For example, we know that running economy is less optimal for child runners compared with adult runners 22 and that children run differently than adults, 21,23,24 and it may be that these movement differences may lead to different mechanisms of shock attenuation and possibly to differing injury mechanisms. Future research is needed to quantify the magnitude and to discern the importance of a lower shock attenuation in children versus adults.…”

Section: Discussionmentioning

confidence: 99%

“…21,23,24 Furthermore, in general, child participants have less running experience than adults. The experiment was planned to provide sufficient instruction and familiarization time for all participants, and children tended to pick up the task of running on a treadmill quickly.…”

Section: Limitationsmentioning

confidence: 99%

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A Description of Shock Attenuation for Children Running

Mercer

Dufek

Mangus

et al. 2010

Journal of Athletic Training

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Vegas. Dr Mangus is now at Texas A&M University-Commerce.Context: A growing number of children are participating in organized sport activities, resulting in a concomitant increase in lower extremity injuries. Little is known about the impact generated when children are running or how this impact is attenuated in child runners.Objective: To describe shock attenuation characteristics for children running at different speeds on a treadmill and at a single speed over ground.Design: Prospective cohort study. Setting: Biomechanics laboratory.Patients or Other Participants: Eleven boys (age 5 10.5 6 0.9 years, height 5 143.7 6 8.3 cm, mass 5 39.4 6 10.9 kg) and 7 girls (age 5 9.9 6 1.1 years, height 5 136.2 6 7.7 cm, mass 5 35.1 6 9.6 kg) participated.Intervention ( Main Outcome Measure(s): We measured leg peak impact acceleration (LgPk), head peak impact acceleration (HdPk), and shock attenuation (ratio of LgPk to HdPk).Results: Shock attenuation (F 2,16 5 4.80, P 5 .01) was influenced by the interaction of speed and sex. Shock attenuation increased across speeds (slow, preferred, fast) for boys (P , .05) but not for girls (P . .05). Both LgPk (F 1,16 5 5.04, P 5 .04) and HdPk (F 1,16 5 6.04, P 5 .03) were different across speeds, and both were greater for girls than for boys. None of the dependent variables were influenced by the interaction of setting (TM, OG) and sex (P $ .05). Shock attenuation (F 1,16 5 33.51, P , .001) and LgPk (F 1,16 5 31.54, P , .001) were different between TM and OG, and each was greater when running OG than on the TM, regardless of sex.Conclusions: Shock attenuation was between 66% and 76% for children running under a variety of conditions. Girls had greater peak impact accelerations at the leg and head levels than boys but achieved similar shock attenuation. We do not know how these shock attenuation characteristics are related to overuse injuries.Key Words: boy and girl runners, impact, lower extremity injuries Key Points N Children attenuated different amounts of shock while running on a treadmill and over ground. N Leg and head peak impact accelerations were greater in girls than in boys. N Boys and girls achieved similar shock attenuation levels under various running conditions. N We do not know the mechanism for shock attenuation in child runners. N When developing rehabilitation programs for children, the practitioner should consider that shock attenuation varies across running speeds and between treadmill and overground running.

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