Effect of three different running gait cues on vertical tibial acceleration

Sex- and age-related differences in kinetics and tibial accelerations during military-relevant movement tasks in U.S. Army trainees

Lower extremity injuries are prevalent in military trainees, especially in female and older trainees. Modifiable factors that lead to higher injury risk in these subgroups are not clear. The purpose of this study was to identify whether external loading variables during military-relevant tasks differ by age and sex in U.S. Army trainees. Data was collected on 915 trainees in the first week of Basic Combat Training. Participants performed running and ruck marching (walking with 18.1 kg pack) on a treadmill, as well as double-/single-leg drop landings. Variables included: vertical force loading rates, vertical stiffness, first peak vertical forces, peak vertical and resultant tibial accelerations. Comparisons were made between sexes and age groups (young, ≤19 years; middle, 20-24 years; older, ≥25 years). Significant main effects of sex were found, with females showing higher vertical loading rates during ruck marching, and peak tibial accelerations during running and ruck marching (p ≤ 0.03). Males showed higher vertical stiffness during running and peak vertical tibial accelerations during drop landings (p < 0.01). A main effect of age was found for vertical loading rates during running (p = 0.03), however no significant pairwise differences were found between age groups. These findings suggest that higher external loading may contribute to higher overall injury rates in female trainees. Further, higher stiffness during running may contribute to specific injuries, such as Achilles Tendinopathy, that are more prevalent in males. The lack of differences between age groups suggests that other factors contribute more to higher injury rates in older trainees.

Is the addition of running retraining to best standard care beneficial in runners with medial tibial stress syndrome? Protocol for a randomised controlled trial

BACKGROUND

Running retraining is commonly used in the management of medial tibial stress syndrome (MTSS) but evidence for its effectiveness is lacking. The primary aim of this study is to determine if the addition of running retraining to best standard care is beneficial in the management of runners with MTSS.

METHODS

This study is an assessor-blinded and participant-blinded, parallel-group, randomised controlled trial. The trial will recruit 64 participants aged between 18 and 45 years, with a clinical diagnosis of MTSS that has affected their running participation for at least four weeks. Participants will be randomised to receive best standard care (control) or running retraining and best standard care (intervention group) over an 8-week period. Best standard care will consist of load management advice, symptom management advice, footwear advice and a strengthening program. Running retraining will consist of a cue to reduce running step length. Outcomes will be measured at weeks 1, 2, 4 and 8. The primary outcome measure will be the University of Wisconsin Running Injury and Recovery Index at week 4. Secondary outcome measures include: (i) Exercise Induced Leg Pain Questionnaire-British Version, (ii) global rating of change scale, (iii) worst pain experienced during a run, (iv) weekly run volume, (v) reactive strength index score, (vi) single leg hop test, (vii) soleus single leg maximum voluntary isometric contraction, (viii) gastrocnemius single leg maximum voluntary isometric contraction, (ix) single leg plantar flexor endurance test, (x) running step length, and (xi) running step rate. Data will be analysed using the intention-to-treat principle.

DISCUSSION

This randomised controlled trial will evaluate if reducing running step length provides additional benefit to best standard care in the management of runners with MTSS over an 8-week period.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry: ACTRN12624000230550.

Cues to land softly and quietly result in acute reductions in ground reaction force loading rates in runners

BACKGROUND

A common gait retraining goal for runners is reducing vertical ground reaction force (GRF) loading rates (LRs), which have been associated with injury. Many gait retraining programs prioritize an internal focus of attention, despite evidence supporting an external focus of attention when a specific outcome is desired (e.g., LR reduction).

RESEARCH QUESTION

Does an external focus of attention (using cues for quiet, soft landings) result in comparable reductions in LRs to those achieved using a common internal focus (forefoot striking while barefoot)?

METHODS

This observational study included 37 injured runners (18 male; mean age 36 (14) years) at the OMITTED Running Center. Runners wore inertial measurement units over the distal-medial tibia while running on an instrumented treadmill at a self-selected speed. Data were collected for three conditions: 1) Shod-Control (wearing shoes, without cues); 2) Shod-Quiet (wearing shoes, cues for quiet, soft landings); and 3) Barefoot-FFS (barefoot, cues for forefoot strike (FFS)). Within-subject variables were compared across conditions: vertical instantaneous loading rate (LR, primary outcome); vertical stiffness during initial loading; peak vertical GRF; peak vertical tibial acceleration (TA); and cadence.

RESULTS

Vertical LR, stiffness, and TA were lower in the Shod-Quiet compared to Shod-Control p < 0.001). Peak vertical GRF and cadence were not different between Shod-Quiet and Shod-Control. Reductions in stiffness and LR were similar between Shod-Quiet and Barefoot-FFS, and GRF in Barefoot-FFS remained similar to both shod conditions. However, runners demonstrated additional reductions in TA and increased cadence when transitioning from Shod-Quiet to the Barefoot-FFS condition (p < 0.05).

SIGNIFICANCE

These results suggests that a focus on quiet, soft landings may be an effective gait retraining method for future research.