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musculoskeletal screening

Musculoskeletal screening: why musculoskeletal screening for athletes matters and how to go about it

Pre-participation screening is a key role of many sports therapists working with recreational club, sub-elite or top-flight athletes, so it is useful from time to time to remind ourselves of the rationale, principles, the dilemmas and the practicalities involved. Here we explain how one aspect of the process – musculoskeletal screening – is carried out with the Queensland Academy of Sport’s men’s water polo squad.

Currently most of the water polo coaches at the QAS will budget for musculoskeletal screening by a sports physiotherapist at least once a season. This is in addition to a thorough medical questionnaire, video analysis by a biomechanist, physiological, psychological, nutritional and strength and conditioning tests.

Why screen?

Performance enhancement / injury prevention

All screening will address one or other of these fundamental aspects of athlete support. Currently the debate is on across the Queensland Academy of Sport as to which side of the line the physiotherapy musculoskeletal screening falls. But it is probably more useful to think in terms of a continuum of athlete testing procedures, with injury prevention at one extreme (where, arguably, the science of medical screening by a doctor would come) and pure performance enhancement at the other (screening by a strength and conditioning specialist). In this continuum, musculoskeletal screening surely comes somewhere midway – if for no other reason than the fact that an injured athlete always performs poorly! Therefore if you manage to prevent even one injury during the season by correcting a biomechanical problem highlighted during screening, that athlete will have performed better.

A small number of sports use a screening programme to help predict performance – such as in dance, where discovery of osseo-ligamentous movement limitations may preclude a young dancer from entering certain academies – but generally the goal is to find ways of improving body mechanics to enable an athlete with potential to maximise it.

At a more technical level, musculoskeletal screening is invaluable for revealing deficits in muscle/ joint flexibility and in muscular stability/control that might lead to overuse injuries. And while the link between correcting these deficits and improved performance can be hard to prove, the growth in popularity of musculoskeletal screening among professionals over the last few decades lends a heavy weight of anecdotal and clinical evidence to support its efficacy.

The more research that is done, the more evidence we have to confirm which tests are useful – and of late physio-philosophers have been debating how to upgrade the scientific validity of screening(1,2). Peter Blanch(1), sports physiotherapist to the AIS, makes the all-important point that while ‘clinical intuition and experience are important factors in the development of our knowledge (as it pertains to screening)’, it is when we cease to be critical of our tests and procedures that we are at risk of relying on ‘faith rather than science’.

Why is it hard to prove the link between screening and improved performance? In essence it is because improved performance is such a multifactorial business. There could be numerous reasons why a top goal shooter in water polo seems to be nailing more balls in the back of the net. It is possible that just one of those reasons is the fact that he can get higher out of the water because his right hip joint has an increased range of flexion, allowing his hip extensors (glut muscles) to work better during his maximal egg-beater kick (see panel above). Hard to prove – but it is certainly a good possibility.

While the scientific evidence for screening is somewhat thin on the ground, there does seem to be a good correlation between certain factors, eg flexibility and:

  • improved maximal strength;
  • greater ability to use the stretchshorten cycle;
  • efficiency of movement
  • improved movement patterns(2).

Physiotherapists are not alone in facing this problem of how valid screening is. It seems that the assessors of strength and power(2) face the same difficulties. Isometric muscle testing and isokinetic dynamometry are believed these days to reveal less than we used to think about an athlete’s proficiency in the dynamic requirements of a given sport. Instead, in the early 1990s, the principle of sports specificity(2) required a shift in strength and power test protocols towards isoinertial (loaded repetitive functional movement) testing.

Past injury assessment

A second core aim of screening is to record the details of significant past injuries, and to assess for any ongoing effects on the mechanics of the injured and non-injured parts of the body. A classic example is how a serious ankle injury, even one that’s 10 years old, may have set a knee problem in motion. The assessment and correction of an ankle joint with reduced gliding motion, proprioception deficits and compensatory subtalar joint pronation should prevent the knee from gradually breaking down.

Looking for injury trends

Recording of injury rates and areas of injury across the whole QAS squad should enable us to identify and correct patterns of injury which may arise from any number of external factors, such as weather, water temperature, intensity of training or competition, etc.

This type of information helps the sporting bodies to understand the importance of screening, and enhances athletes’ willingness to adhere to their exercise regimes.

Practicalities of screening

Thankfully the challenge within the QAS water polo squad is not to convince the coaches and people in authority of the efficacy of musculoskeletal screening, but rather to persuade the athletes, who are often faced with competing demands on time, energy and finances. The best weapon a physiotherapist has, faced with athletes who consider the whole screening process a waste of time, is a professional and enthusiastic approach(1).

For an effective musculoskeletal screening you will need:

  • Equipment: Portable table, goniometer and tape measure. Recording sheet and familiarity with test protocols is essential.
  • Financial resources: ours at QAS are very limited, but sufficient for the task. The head coach has stipulated that he has one hour of time/ dollars allocated for each athlete for the screening and report writing (although we get more time with AIS national level athletes if required).
  • Time: We limit our tests to half an hour, selecting those that give the most useful information about the athletes’ likelihood of injuring a body part (see below).
  • A convenient location: We conduct the screening and interviewing at the QAS gym during workouts.
  • A flexible and tailored approach: At different levels, athletes have different screening priorities: for AIS-level athletes, the main aim of the last screening round was to minimise any chance of injury leading up to the Athens Olympics. The QAS and Junior Developmental Squad were screened with a view to minimising longer-term injury and the acquisition of overall development for good performance, technique and strength.
  • An agreed post-screening procedure: We collate our findings into a report for the athlete and their coach, detailing strengths, weaknesses and recommendations. It is essential that the report is simple and clear enough to be understood by both parties, or else it will end up on the ‘read later’ pile and remain there for ever.

We conduct a post-report interview with athlete and coach together (plus the QAS strength and conditioning specialist and biomechanist, if deemed necessary). We develop a time-framed set of goals, an exercise regime and a monitoring plan. This will always include a reassessment of the athlete, where we can confirm progress and work out any implications for their technique in the pool.

How to develop your screening protocol

You will need to consider:

  • Which tests?
    Your choice of tests will depend on the particular sport’s main actions, building block movements and primary biomechanical requirements. This is certainly the case with a sport such as water polo where the main movement performed (eggbeater stroke) is unlike that of any other sport.

Tests should be generic ones that have been subjected to research, and/or tests used clinically and validated anecdotally (ie, they have not been subjected to the rigours of research, but are sourced from the general body of knowledge and experience of the profession).

The need to follow the logic of sport-specificity is unquestionable, yet it seems to me to be potentially at odds with the need to use tests that are scientifically validated, because in reality only a handful of appropriate tests may fall into the latter category(2).

For water polo, the major jobs that the body has to do (with corresponding biomechanical requirements) are:

  • eggbeater kick(3,4): stable pelvis; flexible and strong quadriceps/ hamstrings, hip flexors/extensors, internal/external rotators and abductors/ adductors, tibial internal rotators, foot plantar flexors/invertors and dorsiflexors/ evertors; left/right symmetry;
  • freestyle swimming: stable pelvis and scapula; flexible and strong quads, rotator cuff, pecs, lats; cervical/thoracic spine mobility;
  • shooting/throwing: as for freestyle but even higher levels of gleno-humeral muscular control and coordination; coordination of kinetic chain for effective force transmission across many body segments;
  • one-on-one contesting: high levels of pelvic, scapular and glenohumeral stability as the foundation for strength and power.

The eggbeater kick:

further reading

‘Strength, Flexibility and Timing in the Eggbeater Kick’, Professor Ross Sanders – Director, Centre for Aquatics Research and Education, University of Edinburgh, can be read at www.coachesinfo.com/category/ water_polo/5/

  • Inter-tester reliability
    To reduce subjectivity, screening tests need to be very simple and with clear protocols as to positions, measures taken, standards required, equipment used, and ease of recording. Error margins need to be as low as possible(5) so that different therapists can achieve similar results when testing the same athlete.
  • Intra-tester reliability
    Similarly tight procedural controls should apply to ensure minimum room for error each time the same therapist does the same tests on the same athlete.
  • Repeatability (reproducibility)
    If the tests are shown to be reliable in the above two ways, then they will be repeatable. It may sound obvious but clinically this is essential if we are going to get useful data that accurately reflects the athlete’s current biomechanical state. If we have tested the flexibility of their rotator cuff and we find it to be tight, we can now say with confidence that another tester will also find it tight, and that, crucially, it actually is a tight rotator cuff!
  • Sport-wide injury profiling
    The injury profile of the sport will also help us to decide which tests we should be doing. The Australian Sports Commission’s report on injuries sustained over a 13-year period in elite water polo(6), for instance, found that 73.4% of injuries over the 13 years of the study were acute in onset, with one in five becoming chronic (lasting more than six weeks). Yet among the smaller group of over-use injuries, an alarming 47% became chronic. We surmised that these overuse injuries are the most important ones to screen for, because they are most realistically preventable.

Sport profiling also tells us that water polo players mainly suffer shoulder injuries (24.1% of all injuries), facial injuries (15.5%) and hand injuries (14.7%). So the shoulder comes high on our priority scale for assessment(1,6-8).

  • Alignment with other screening protocols
    We consulted the protocols developed at AIS level for water polo. However, differences in time and money available may mean you have to pick and choose which test protocols to follow from elsewhere.

Screening schedule

In 2002 and 2003 our water polo screening was done at the beginning of the training season in September, with a view to preparing the players for their competitive season (November to April/May).

While the literature has suggested that the ideal time for a pre-season screen should be four to six weeks ahead of season’s start(9), I believe this is not long enough to allow athletes to make real positive changes to faulty mechanics.

Recently the case has successfully been put for QAS’s water polo screening to be moved to early in the off-season (six to eight weeks before season’s start) for the following reasons:

  • players’ bodies still reflect their competitive state, as their biomechanics have not yet been subjected to the deconditioning of the off season. I believe the information more accurately reflects any tendencies to tightness and/or poor movement patterns, because deconditioning/ rest will make things look worse or better than they are during the competitive phase;
  • players’ bodies are more conducive to flexibility and stability development during the off-season as the loading on their systems is at a minimum;
  • mentally they are able to prioritise this type of training, instead of seeing it as an extra imposition;
  • athletes will have more time to work on any on-going injuries by seeking massage, physio, etc.

References

  1. Blanch P. It’s Time to Screen Screening. Sportslink Jan 2004 pp1-5.
  2. Tumilty D, Logan P, Clews W and Cameron D. Protocols for the assessment of elite water polo players. Physiological tests for Elite Athletes, Ed CJ Gore; Human Kinetics, Australian Sports Commission. 2000.
  3. McMaster W. Isokinetic torque imbalances in the rotator cuff of the elite water polo player. Amer Jour Sports Medicine v19 (1) 1991 p72-75.
  4. Sanders RH. Analysis of the eggbeater kick used to maintain height in water polo. Jour Applied Biomechanics v15 (3) Aug 1999 p2284-291.
  5. Penfold Blanch and Martin. musculoskeletal Screening in Cycling. Sportslink Jan 2004 pp10-12.
  6. Annett P, Fricker PA and McDonald WA. Injuries to elite male water polo players over a 13-year period. New Zealand Journal of Sports Medicine, 28(4): 78-83. 2000.
  7. Brooks JM. Injuries in Water Polo Clinics. Sports Medicine v18 (2)Apr 1999; p313-319.
  8. Colville JM, Markman BS. Competitive Water Polo: upper extremity injuries. Clinics in Sports Medicine v18(2)1999 p305-312.
  9. Lombardo JA. Pre-participation Physical evaluation. Primary Care. 11(1):3- 21, 1984.

 

musculoskeletal screening