THE EDGE

(EMD) and better reflects the ability to pro- tect the joint in a threatening situation. This parameter has been found to be more useful when assessing safe return to sport. The exact linkage between such factors and susceptibility to injury is the subject of this group’s ongoing research programmes. It is, however, interesting to note that EMD, rate of force development and mea- sures of dynamic proprioception are more dramatically influenced by injury and surgery/rehabilitation processes compared with the standard contemporary measures of neuromuscular performance such as strength (1,2).

5. Movement control The concept of proprioception is still not

clearly defined although it is stated to be of great importance in rehabilitation. Standard techniques of assessment such as joint position sense have been found to be of little value.

Tests of dynamic proprio-

ception are being evaluated at the ESA centre both on the bench and in running environments.

6. Motion analysis However many bench tests are performed, they never replicate the field of play. The ESA unit has a 16 camera, real time 3-D motion analysis system with 5 force plates and the advantage of remote, telemetric electromyographic (EMG) data acquisition. A 90 minute game simulation for football can be performed (3).

With the aid of a magnetic resonance scan (MRI) of the knee, it is also able to show the strain patterns in the ACL (5).

Such

“visualisation” of ACL function has never previously been performed. It is possible that the dynamic motion analysis charac- teristics will give the most confident indi- cator of safe resumption of sport following such injuries as ACL rupture.

Each of the tests give relevant results but together form the basis of the scientific testing of sports injury.

In the long-term repeated high-precision testing can be used to produce a fuller set of data on the player’s physical state over time.

The first visit and testing can be

used as a benchmark while subsequent vis- its can identify changes in this benchmark standard. The data can give an accurate view of a player’s fitness level at any given time, drive the decision for the correct time for a player’s return from injury and identi- fy existing but hidden injuries a player might not be aware of and may be com- pensating for.

Mr Dai Rees is a full time consultant in sports injury surgery at the National Centre for Sports Injury Surgery, at Oswestry Orthopaedic Hospital. He is also orthopaedic surgeon to the Football Association’s School of Excellence at Lilleshall and several other Premier and Football League Clubs.

Dr Nigel Gleeson is director of research at the ESA. He lectures in kinesiology at the University of Wales and has been involved in human performance mea- surement for over 14 years.

References 1. Doyle J, Gleeson NP, Rees D. Psychobiology and the athlete with ACL injury. Sports Med 1998; 26(2)(Dec):379-393 2. Gleeson NP, Rees D, Doyle J et al. The effect of ACL surgery and acute physical rehabilitation on musculoskeletal modelling associated with the knee joint. J.Sp.Sci (in press) 3. Gleeson NP, Reilly T, Mercer TH, Rakowski S, Rees D. Influence of acute endurance activity on leg neuromuscular and musculoskeletal per- formance. Med Sci Sp Ex. 1998;30:596-608 4. Gleeson NP, Rees D, Rakowski S. Reliability of indices of anterior tibio-femoral ligamentous function. In Engineering of Sport, Haake (Ed) 1996 Balkema Rotterdam, 37-42 5. Attfield S, Gleeson NP, Pickering P, Rees D. Assessment of the effects of dynamic exercise on ACL strain. Gait & Posture 1997;Vol 6:263-5