gms | German Medical Science

Objective: Medial tibial stress syndrome (MTSS) is one of the most common overload leg injuries in athletes. Excessive pronation of the foot while standing has been found to be intrinsic risk factors in multiple prospective studies. The mid and the hindfoot has been less focused on the literature. The objective of this work was to dynamically assess the plantar pressure distribution in athletes suffering from MTSS with special reference to the posterior aspect of the foot.

Material/Methods: Dynamic foot pressure measurements were analyzed in 25 athletes (15 men and 10 women) of high competitive level with symptoms of MTSS (38 tibias) along a year season. Average age was 18 years, height 180 cm, weight 60,9 kg and BMI 20.9. There were 17 athletes practicing a cyclic-aerobic athletics modality and 8 performing an explosive-anaerobic type of exercise. Control group consisted on 20 healthy athletes (12 men and 8 women) of the same competitive level and matched in age, weight, BMI and training hours. An insoles system (Biofoot^®/IBV) with telemetry transmission information was used to record the pattern of plantar loadings. The plantar surface of foot was divided in 3 zones (hindfoot, midfoot, forefoot) that, in turn, were divided in 3 subareas (medial, central and lateral). Dynamical measurements were recorded during free running.

Results: Among symptomatic athletes there were 28% with hyperpronated foot. Total plantar pressure was higher in controls than in MTSS athletes but with the same distribution by hindfoot, midfoot, and forefoot. As compared to healthy athletes, those with MTSS showed a different load distribution in the digital areas with lower average pressure at the central digits (850 kPa vs 1400 kPa; p<0.05) and more percentage of the total load of the digital areas on the first toe ((37% vs 24%; p<0.05). In the metatarsal areas, average total pressures were lower in MTSS athletes being significant only at the first metatarsal region (620 KPa vs 1050 kPa; p<0.01). At the midfoot, athletes with MTSS had more percentage of the total load on the lateral region (68% on the lateral and 32% on the medial midfoot). Healthy athletes had an inverse distribution (38% on the lateral midfoot and 62% on the medial aspect). These differences were clearly significant on both midfoot sides (p<0.01). In the talar region MTSS athletes had also lower average total load than healthy controls (790 kPa vs 1270 kPa; p<0.01). When pressures were analyzed according to the time sequence of plantar loading, MTSS athletes first loaded the talar region, second the lateral midfoot and afterwards the medial aspect of the midffot. More interesting was the early discharge of the talar region that was seen at an average of 31.6% of the total period of the footprint. Healthy athletes discharged the talar region at an average of 76.3% of the total footprint period (p<0.001).

Conclusion: Athletes with MTSS showed a different mechanical pattern during gait. The baropodometric findings indicated that in MTSS athletes the foot had an attitude of equino-varus talus due to retraction of the muscles of both superficial and deep posterior tibial compartments. This study emphasizes the importance of baropodometric studies in top athletes in order to improve the biomechanical strategy to prevent overload injuries.