Is Skater’s Cramp a Task-Specific Dystonia?

Skater’s cramp is a mysterious and debilitating movement disorder that affects Olympic and amateur speed-skaters alike, often spelling the end of their careers. Affected skaters will often experience a sudden jerk of their foot before placing their skate on the ice after a completed stroke causing instability and risking a fall. Many explanations for skater’s cramp have been proposed, but ensuing treatments have been unsuccessful. Based on clinical and subjective assessments of individual cases of skater’s cramp by neurologists at the UMCG, the diagnosis task-specific dystonia was proposed. The purpose of this thesis was to further investigate this proposed diagnosis, using quantitative measures to help answer our major research question: is skater’s cramp a task-specific dystonia? In multiple experiments collecting clinical, movement, muscle, and psychometric data, results were supportive of the answer: yes. Although not definitive, this evidence is an important first step in better understanding this mysterious disorder, and may eventually lead to more informed and effective treatments for those affected

UNDIAGNOSED MOVEMENT DISORDER IN SPEED SKATING: A POSSIBLE FORM OF TASK SPECIFIC DYSTONIA

This study aimed to investigate the bio-mechanics of a mysterious and undiagnosed movement disorder appearing in the Netherlands among expert speed skaters known as ‘zwabbervoet’ or, skater’s cramp. An unpublished manuscript looking at 5 affected skaters indicates that the disorder may be a form of task specific dystonia. Using a novel tailor-made program for analyzing speed skating, this study looked at the kinematic features of skater’s cramp. The results showed skater’s cramp was person specific, that it had a clear, consistent asymmetry that was predictable across multiple gait cycles irrespective of speed or intensity of skating. A more in depth analysis combining electromyography and force measurement with the current analysis is in development to further investigate the task specificity of this disorder

Is Behavioural Therapy a New Treatment Option for Task-Specific Dystonia in Athletes? A Case Series

Background: Task-specific dystonia is a movement disorder of the central nervous system characterized by focal involuntary spasms and muscle contractions, which can negatively affect performance of a specific task. It can affect a wide range of fine motor skills, also in athletes. Current management of task-specific dystonia includes mainly prescribing drugs, exercise therapy or botulinum injections to the affected muscles. Psychological interventions for athletes suffering from task-specific dystonia have not been described extensively so far. Methods: We present a case-series of 4 different advanced skill-level athletes with suspected task-specific dystonia, which had a major impact on their performance. They all received treatment consisting of a combination of standardized behavioural therapy and relaxation techniques in the form of hypnosis in a total of 8 sessions in a 16-week time period. Results: After treatment, all athletes returned to their original high level of sport performance without further symptoms of their suspected task-specific dystonia. Discussion: Behavioural therapy in combination with a relaxation technique seems to be a safe and promising treatment for athletes with suspected task-specific dystonia. Further studies in a larger, preferably randomized controlled trial, are warranted to evaluate if this treatment strategy is effective in athletes with suspected task-specific dystonia.</p

Muscular and kinematic features in speed skaters indicate a task-specific dystonia

Objective: Skater's cramp is a movement disorder in speed skaters. We investigated whether affected skaters matched the disease profile of task-specific dystonia, specifically whether there was evidence of maladaptive muscle activity occurring simultaneously with aberrant movements (jerking). We further examined different skating intensities, positing no change would be more indicative of task-specific dystonia. Methods: We analyzed video, kinematic and muscle activity in 14 affected skaters. We measured the angular velocity and electromyographic activity of normalized speed skating strokes using one dimensional statistical non-parametric mapping. Skaters were matched with comparably skilled controls, and filled out a bespoke clinical questionnaire. Results: Skaters’ impacted leg showed over-activation in the peroneus longus, tibialis anterior and gastrocnemius that coincided with higher foot movement compared to their healthy leg and controls. This pattern persisted regardless of skating intensity. Clinical features indicated it was task-specific and painless with common trigger factors including stress, equipment change, and falling. Conclusions: We showed aberrant muscular and kinematic activity in a movement disorder in speed skaters indicative of task-specific dystonia. Significance: Understanding skater's cramp as a task-specific dystonia could reduce the damage that misdiagnosis and unsuccessful invasive operations have caused. Our quantitative method has value in testing future treatment efficacy.</p

Skater's Cramp:A Possible Task-Specific Dystonia in Dutch Ice Skaters

Background Skater's cramp is an involuntary lower leg movement in skilled speed skaters. We aim to evaluate whether skater's cramp is compatible with task-specific dystonia. Methods A case-control study tested 5 speed skaters exhibiting symptoms of skater's cramp and 5 controls. Affected skaters completed a standardized questionnaire and neurological examination. Video analyses included skating normally, intensely, and with extra mass around the skater's ankles. An Inertial Motion Capturing (IMC) device mounted on both skates provided angular velocity data for both feet. Results Median time of onset of skater's cramp occurred after 12 (range 3-22) years of speed skating. Skater's cramp appeared as task specific; its onset was sudden and correlated to stress and aberrant proprioception. Symptoms presented acutely and consistently during skating, unilaterally in 4 and bilaterally in 1 skater. Visually, skater's cramp was an active, patterned, and person-specific jerking of a skater's foot, either exo- or endorotationally. It presented asymmetrically, repeating persistently as the foot neared the end of the swing phase. The skater's affected leg had a longer swing phase (median, 1.37 [interquartile range {IQR}, 0.35]/1.18 [IQR, 0.24] seconds; P 0.05). No significant differences between legs were detected in the control group. Conclusions Observed clinical, visual, and kinematic data could be an early and tentative indication of task-specific dystonia

Life is unfair, and so are racing sports: some athletes can randomly benefit from alerting effects due to inconsistent starting procedures.

The Olympics are the world's largest sporting events, attracting billions of viewers worldwide. Important parts are racing sports, such as running, swimming and speed skating. In these sports, athletes compete against each other in different heats to determine who wins the gold, or who is granted a place in the final. Of course, the gold goes to whoever is the most talented and has trained the hardest. Or does it? Here we argue that subtle differences between athletes' starts can bias the competition, and demonstrate this in the results of speed skating at the 2010 Winter Olympics. This bias could be removed by simple alterations to current starting procedures. The proposed change would greatly improve racing sport fairness, which currently suffers from an injustice that disadvantages not only athletes, but entire nations rooting for them

Life is unfair, and so are racing sports: Some athletes can randomly benefit from alerting effects due to inconsistent starting procedures

The Olympics are the world's largest sporting events, attracting billions of viewers worldwide. Important parts are racing sports, such as running, swimming and speed skating. In these sports, athletes compete against each other in different heats to determine who wins the gold, or who is granted a place in the final. Of course, the gold goes to whoever is the most talented and has trained the hardest. Or does it? Here we argue that subtle differences between athletes' starts can bias the competition, and demonstrate this in the results of speed skating at the 2010 Winter Olympics. This bias could be removed by simple alterations to current starting procedures. The proposed change would greatly improve racing sport fairness, which currently suffers from an injustice that disadvantages not only athletes, but entire nations rooting for them

Life is unfair, and so are racing sports: Some athletes can randomly benefit from alerting effects due to inconsistent starting procedures

The Olympics are the world's largest sporting events, attracting billions of viewers worldwide. Important parts are racing sports, such as running, swimming and speed skating. In these sports, athletes compete against each other in different heats to determine who wins the gold, or who is granted a place in the final. Of course, the gold goes to whoever is the most talented and has trained the hardest. Or does it? Here we argue that subtle differences between athletes' starts can bias the competition, and demonstrate this in the results of speed skating at the 2010 Winter Olympics. This bias could be removed by simple alterations to current starting procedures. The proposed change would greatly improve racing sport fairness, which currently suffers from an injustice that disadvantages not only athletes, but entire nations rooting for them