The GRONORUN study: is a graded training program for novice runners effective in preventing running related injuries? Design of a Randomized Controlled Trial

BACKGROUND: Running is a popular form of recreational exercise. Beside the positive effects of running on health and fitness, the risk of a running related injury has to be considered. The incidence of injuries in runners is high and varies from 30–79%. However, few intervention studies on prevention of running related injuries have been performed and none of these studies involved novice runners. METHODS: GRONORUN (Groningen Novice Running) is a two armed randomized controlled trial, comparing the effects of two different training programs for novice runners on the incidence of running related injuries. Participants are novice runners, who want to train for a four mile running event. The control group will train according a standard 8 week training program. The intervention group will use a more gradual, 13 week training program which is based on "the ten percent training rule". During the thirteen week follow up participants register information on running and RRI's in an internet based running log. The primary outcome measure is RRI. An injury is defined as a musculoskeletal ailment of the lower extremity or back, causing a restriction of running for at least one week. DISCUSSION: The GRONORUN trial is the first randomized controlled trial to study a preventive intervention in novice runners. Many different training programs for novice runners are offered, but none are evidence based

Differences in Knee Joint Stabilization Between Children and Adults and Between the Sexes

Background: Differences in knee joint stabilization between children and adults and between the sexes are not fully understood. Purpose: To compare the knee laxity and the dynamic tibial translation between (1) children and adults, (2) girls and boys, and (3) women and men. Study Design: Controlled laboratory study. Methods: Sixty-seven children (aged 8-13 years) and 63 adults (aged 18-30 years) without previous knee injuries participated. Sagittal tibial translation was measured during the instrumented Lachman test at 90 N and 134 N (knee laxity) and during gait (dynamic translation). Tibial translation was recorded with an electrogoniometer. Results: Knee laxity was greater in children than in adults (Lachman test at 90 N: 9.1 +/- 2.9 vs 7.3 +/- 2.7, respectively; P < .001). In contrast, dynamic tibial translation during gait did not differ between children and adults. Girls and boys did not differ in knee laxity or maximum anterior tibial translation during gait, and men and women did not differ in knee laxity. Women had greater dynamic tibial translation during gait than men (7.8 +/- 2.7 vs 5.7 +/- 3.0, respectively; P = .004). Conclusion: Children had greater knee laxity than adults, whereas the dynamic tibial translation did not differ. In adults, knee laxity did not differ between the sexes, but dynamic tibial translation was greater in women. Clinical Relevance: Children and men had less dynamic tibial translation during gait in proportion to their maximum knee laxity. The observed less dynamic tibial translation in children and adult men might be related to their reduced risk of sustaining an anterior cruciate ligament injury