Ankle and Foot Contributions to Extreme Plantar- and Dorsiflexion in Female Ballet Dancers
Foot & Ankle International, Feb 1, 2011
Background: Female ballet dancers require extreme ankle motion. The objective of this study was t... more Background: Female ballet dancers require extreme ankle motion. The objective of this study was to quantify the relative contributions of the ankle and various foot joints to extreme plantarflexion (PF) and dorsiflexion (DF) in female ballet dancers using an X-ray superimposition technique and digital graphics software. Materials and Methods: One asymptomatic ankle was studied in each of seven experienced female ballet dancers. Three lateral weightbearing X-rays were taken of each ballet dancer's ankle: en pointe (maximum PF), in neutral position, and in demi-plié (maximum DF). Using graphics software, a subject's three X-ray images were superimposed and the tall were aligned. On each image the tibia, navicular, intermediate cuneiform, and first metatarsal were marked. Positional differences of a bone's line among the three images demonstrated angular movement of the bone in degrees. The neutral position was the reference from which PF and DF of the bones were calculated. Results: The talocrural joint contributed the most motion of any pair of bones evaluated for both PF and DF, with mean movements of 57.6 ± 5.2 degrees en pointe and 24.6 ± 9.6 degrees in demi-plié. Approximately 70% of total PF and DF were attributable to the talocrural joint, with the remaining 30% coming from motion between adjacent pairs of the studied foot bones. Conclusion: Superimposed X-rays for assessing ankle and foot contributions to the extreme positions required of female ballet dancers offer insight into how these positions are attained that is not available via goniometry. Clinical Relevance: Functional information gained from this study may assist clinicians in assessing ankle and foot pain in these individuals.
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Papers by Matthew Wyon
intensities at 30%, 60%, and 90% of maximum range of movement (mROM) on the inflammatory response of the right
hamstring muscle. Methods: A randomised within-subject trial was conducted with 11 healthy recreationally active
males over a three week period. Participants were strapped into an isokinetic dynamometer in the supine position, with
the right knee fastened in a knee immobilizer. After randomising the ROM percentages, the hamstring muscle was
moved to one of the three chosen ROM percentages for that week and held there for 5 x 60 seconds followed by a 10
second rest between repetitions. A 5ml blood sample was collected pre-, immediately post, and at 24 hours post
intervention for high sensitivity C-reactive protein (hsCRP) assessments. Results: Significant increases in hsCRP levels
were observed between 30% mROM and 90% mROM (p=0.004) and 60% mROM and 90% mROM (p=0.034), but not
between 30% and 60% (p>0.05). Conclusions: Muscle stretching at submaximal levels does not elicit a significant
systemic inflammatory responses.