Kathleen S. Thomas and Dr. Mark Ricard, Physical Education
Medial Tibial Stress Syndrome (MTSS) is defined as chronic leg pain in the distal two-thirds of the medial border of the tibia where stress fractures and exertional compartmental syndrome have been ruled out.1,2,3,5 This syndrome is induced by intense, repetitive, high impact exercise such as running and in the case of dancers, jumping and leaping.
There are numerous studies that report a high correlation between hyperpronation of the foot and the incidence of MTSS in runners.1,2,3,4 However, the available MTSS research done on dancers specifically is comparatively small. While many similarities exist between runners and dancers, the foot strike, leg orientation, vertical impact and shoeware are notably different. Because of these dissimilarities, it cannot be assumed that the running data is automatically applicable to the dancer. The purpose of this study was to examine a possible correlation between pronation and the incidence of MTSS in a weight-bearing dynamic assessment as it related specifically to the dancer while executing the Irish step Cut 1,2.
Methods and Procedures
The legs of 10 female Irish folk dancers from the International Folk Dance Ensemble at Brigham Young University with performance level Irish soft shoe skills, were evaluated. The history of MTSS was bilateral in most, but not all, dancers. Therefore, the groups were divided into legs instead of dancers. The legs with a history of reoccurring MTSS symptoms were placed in one group (MTSS group). The legs that had no history of MTSS symptoms were placed in another group (control group). Due to uncontrollable circumstances, three of the legs did not meet the criteria for filming on the day of data collection, therefore, the legs of the MTSS group (N=7) and the legs of the control group (N=10) are not evenly divided.
Reflective marker balls (1cm) were attached to specific anatomical landmarks on the dancer=s lower body. The dancer performed a series of Irish Cut 1,2’s while being filmed by 6 Falcon Motion Analysis cameras. This series was repeated for a total of 10 trials on each leg. The average total number of footfalls for each leg was 68. A single selection of traditional Irish music was used for all trials for each dancer.
Fatigue was highly monitored and is not believed to be a confounding variable in this study.
The appropriate computer software analyzed each footfall for degrees of pronation and aspects of velocity associated with pronation. The values for each dancer were calculated and then combined to form mean and standard deviation values for each group. A T-test was then performed to calculate statistical significance.
The MTSS group showed a significant increase in values for both maximum pronation (the greatest amount of pronation produced during the footfall) and in total pronation (a measurement involving the angle of pronation or supination of the foot at touchdown combined with the maximum pronation angle to indicate total range of movement) as compared to the control group.
The maximum velocity of pronation (peak angular velocity of pronation produced during the footfall) in the MTSS group was also significantly higher when compared to the control group. However, there was no significant difference between the groups in terms of time to maximum velocity of pronation (time elapsed between the toe strike and when the maximum velocity of pronation occurred).
The biomechanical aspects of the lower leg have many variables. The data from this study indicates that hyperpronation may indeed be an influential mechanism for creating this syndrome in dancers as well as runners.
Researching MTSS in a dynamic setting allows for better replication of dance-specific movement, thus increasing the accuracy of the data. The correlation between increased pronation and the incidence of MTSS among dancers executing the Irish step Cut 1,2 was established. This data provides a base from which further dance-related research may be developed.6
- Beck, Belinda R. Tibial stress injuries. Sports Med. 26:265-279, 1998.
- Brukner, Peter. Exercise-related lower leg pain: An overview. Med. Sci. Sports Exer. 32.3 Suppl.:S1-S3, 2000.
- Kortebein, Patrick M., Kenton R. Kaufman, Jeffrey R. Basford, Michael J. Stuart. Medial tibial stress syndrome. Med. Sci. Sports Exer. 32.3 Suppl.: S27-S33, 2000.
- Michael, Roger H. and Lawrence E. Holder: The soleus syndrome, a cause of medial tibial stress (shin splints). Am. J. Sports Med. 13.2:87-94.1985.
- Sommer, Hillel M., Stephen W. Vallentyne. Effect of foot posture on the incidence of medial tibial stress syndrome. Med. Sci. Sports Exer. Aug.:800-804, 1994.
A special thanks to Gary Christopher and Jody Brucker.