Foot contact angle variability during a prolonged run with relation to injury history and habitual foot strike pattern.

Foot strike pattern and movement variability have each been associated with running injuries. Foot contact angle (FCA) is a common measure of strike pattern. Thus, variability in FCA could be an important running injury risk factor. The purposes of this study were to compare (a) foot contact angle (FCA) and its variability between runners with and without injury history and, (b) FCA variability between habitual rearfoot strike (RFS) and non-RFS runners during a prolonged run. Twenty-three runners with and 21 without injury history participated. Motion capture was used to collect kinematic data during a 40 min treadmill run. Average FCA and its variability were compared between injury groups and among four time points. FCA and its variability were not different between runners with and without injury history or among time points during the run. FCA variability was lower in non-RFS compared to RFS runners (P < 0.001). Lower FCA variability in non-RFS runners may have implications for higher injury risks due to repeated localized tissue loading. Prospective analyses on the effects of lower FCA variability on injury risk are needed.

The measurement of upper body alignment during the golf drive.

Transverse plane rotations of the upper body are often estimated during the golf swing. The aim of this study was to determine the agreement between upper body alignments measured using markers attached to the thorax and markers on the acromion process during the golf drive. Three-dimensional coordinate data from nine markers were collected (300 Hz) during eight golf drives for 10 participants. The transverse plane alignment of the upper body was calculated using three techniques: inter-acromion vector, thorax vector, and Cardan angles. Agreement between the methods was then assessed using intra-class correlation and 95% limits of agreement. Our results suggested that the thorax vector can be used to provide an accurate estimation of thorax alignment at all stages of the golf swing (R > or = 0.97, systematic difference < 1.0 degrees , random difference < 3.8 degrees ). The inter-acromion vector gave an accurate estimation of thorax alignment at address (R = 0.90, systematic difference = 0.0 degrees , random difference = 4.3 degrees ) but it should not be used to estimate thorax alignment at the top of the backswing (R = 0.32, systematic difference = -16.0 degrees , random difference = 8.7 degrees ) or impact (R = 0.90, systematic difference = -5.1 degrees , random difference = 8.3 degrees ) during the golf drive.

Anatomy of the collateral ligaments of the human ankle joint.

Damage to the collateral ligaments of the ankle is relatively common, particularly the lateral ligaments; therefore, it is important to be aware of the detailed anatomy and frequency of variation of the individual ligaments. Only two reports of collateral ligaments dimensions were found in the literature, neither of which considers all of the individual components of the collateral ligament complex. Osteoligamentous preparations of the collateral ligaments of 40 ankles from 20 cadavers of European Caucasian origin were studied, from which mean values for the length and width of the individual components were determined, together with their frequency of occurrence. For the collateral ligaments of the ankle as a whole, the ligamentous dimensions determined in this study are similar to those reported previously. The data presented in this study are, therefore, a valuable addition to the small pool of data that exists concerning the dimensions of the collateral ligaments of the human ankle joint. These data may be of value when considering surgical repair or reconstruction of traumatized collateral ligaments, especially because any undue foreshortening of the ligaments may reduce the range of motion possible at either the ankle or subtalar joints, or both. It is possible that in extreme cases, such a reduction in the range of motion may modify gait patterns and the transmission of stresses across the joints of the foot and lower limb.

A comparison of four in vivo methods of measuring tibial torsion.

Tibial torsion, twisting of the tibia about its longitudinal axis, varies during development and early childhood. Knowledge of the normal range of tibial torsion at various ages and its accurate clinical measurement is important in the assessment of the extent of a torsional deformity. To evaluate tibial torsion a reliable technique for its measurement in vivo is therefore required. The aim of this study was to determine which of 4 existing in vivo methods of measuring tibial torsion was the most accurate and had the highest repeatability, by comparing them with direct measurement of the tibia. A wide range of mean values for tibial torsion was observed, using the various techniques, with none of the indirect techniques employed having a strong correlation with direct measurement of tibial torsion. The repeatability of the indirect techniques was observed to be low both in cadavers (n = 4) and the living (n = 3). Since none of the in vivo techniques appear to measure true tibial torsion or be of a reasonable repeatability, alternative easy to use and inexpensive methods need to be developed. Accurate clinical measurement of tibial torsion is important in the assessment of the extent of a torsional deformity. It is recommended that data gained using the methods reviewed here are interpreted with caution.

The medial collateral ligaments of the human ankle joint: anatomical variations.

This study aimed to investigate anatomical variations within the medial collateral ligament complex of the human ankle joint. Osteoligamentous preparations of 40 ankles from 20 cadavers were studied. Six different component bands of the medial collateral ligament complex were observed: four superficial bands (tibiospring, tibionavicular, superficial posterior tibiotalar, and tibiocalcaneal ligaments), of which only the tibiospring and tibionavicular ligaments were constant, and two deep bands (deep posterior tibiotalar and deep anterior tibiotalar ligaments), of which only the deep posterior tibiotalar ligament was constant. No pattern was observed in the distribution of additional bands. A consistent and universally accepted system for naming the various bands of the medial collateral ligament is necessary to enable easy and accurate comparisons between studies. We suggest that this system should be based on the attachments of the ligaments.