A complete posterior tibial stress fracture that occurred during a middle-distance running race: a case report

Speed and surface steepness affect internal tibial loading during running

BACKGROUND

Internal tibial loading is influenced by modifiable factors with implications for the risk of stress injury. Runners encounter varied surface steepness (gradients) when running outdoors and may adapt their speed according to the gradient. This study aimed to quantify tibial bending moments and stress at the anterior and posterior peripheries when running at different speeds on surfaces of different gradients.

METHODS

Twenty recreational runners ran on a treadmill at 3 different speeds (2.5 m/s, 3.0 m/s, and 3.5 m/s) and gradients (level: 0%; uphill: +5%, +10%, and +15%; downhill: -5%, -10%, and -15%). Force and marker data were collected synchronously throughout. Bending moments were estimated at the distal third centroid of the tibia about the medial-lateral axis by ensuring static equilibrium at each 1% of stance. Stress was derived from bending moments at the anterior and posterior peripheries by modeling the tibia as a hollow ellipse. Two-way repeated-measures analysis of variance were conducted using both functional and discrete statistical analyses.

RESULTS

There were significant main effects for running speed and gradient on peak bending moments and peak anterior and posterior stress. Higher running speeds resulted in greater tibial loading. Running uphill at +10% and +15% resulted in greater tibial loading than level running. Running downhill at -10% and -15% resulted in reduced tibial loading compared to level running. There was no difference between +5% or -5% and level running.

CONCLUSION

Running at faster speeds and uphill on gradients ≥+10% increased internal tibial loading, whereas slower running and downhill running on gradients ≥-10% reduced internal loading. Adapting running speed according to the gradient could be a protective mechanism, providing runners with a strategy to minimize the risk of tibial stress injuries.

Treatment and Rehabilitation Approaches for Stress Fractures in Long-Distance Runners: A Literature Review

Stress fractures (SFs) result from repetitive mechanical stress on bones, leading to an imbalance in osseous tissue adaptation and resulting in cortical fractures. The majority of SFs occur in the lower limb due to excessive mechanical loads. Long-distance runners are highly susceptible to SFs, especially when there is a significant increase in the load or intensity of their activity. Various intrinsic and extrinsic factors contribute to the development of SFs. Common SF locations in long-distance runners include the tibial shaft, femur, metatarsal, and pelvic region. Diagnosis may be delayed due to mild symptoms and unremarkable imaging tests. However, the chronicity and recurrence of misdiagnosed SFs may lead to debilitating complete fractures that are even more challenging to treat. In this review, we present data revealed from published case reports and case series studies obtained through PubMed and Embase databases focusing on the management of SFs in long-distance runners and correlate treatment outcomes with rehabilitation and return to high-level athletic performance.