The Isometric Mid-Thigh Pull Considerations for Integration into a High Performance Program
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The document provides an overview of using isometric mid-thigh pulls (IMTP) to assess athletic performance. It discusses using the IMTP test with golfers, divers, and developmental athletes as it provides a safe, reliable, and valid method of testing maximal strength. The document outlines the IMTP testing protocol and how to analyze peak force, rate of force development, and impulse from the test results. It provides normative data and discusses using IMTP results along with other tests for specific strength diagnosis and monitoring real changes in performance over time rather than typical error. The document emphasizes that while maximal strength is important, other qualities like reactive, eccentric, and dynamic strength also contribute to athletic performance.
The Isometric Mid-Thigh Pull Considerations for Integration into a High Performance Program
- 2. Overview • Personal experience • Justification for use • Isometric tests and athletic performance • Protocol • Peak Force or Rate of Force Development • Data Analysis • Specific Strength Diagnosis
- 3. Personal Experience • Golfers – Exceptionally skilled performers but lacking in athletic qualities • Divers – Hypermobile athletes with a disposition to lower back pain – flexion based sport • Developmental athletes – Field hockey – how reliable is squatting? In all three cases I needed a safe, reliable and valid method of testing maximal strength.
- 4. Justification for the IMTP • Reliable • Peak force data is highly reliable – ICC 0.90-0.99 • RFD may not be reliable – familiar athletes only • Valid • It assesses the exact physical quality that we want to determine, maximum strength • Unskilled and requires limited familiarization • Low incidence of injury • Common concern with squatting • Kilgallon (2008)
- 5. Is Isometric Testing Appropriate? • Isometric testing was previously viewed as being inappropriate due to the fact that a range of studies had found poor correlations with dynamic performance – Abe et al. (1992), Baker et al. (1994), Fry et al (1991), Murphy and Wilson (1996), Murphy et al. (1994), Wilson et al (1995) • However there is now a growing body of evidence to suggest the opposite. – Haff et al. (1997), McGuigan and Winchester (2008), McGuigan et al. (2006), Stone et al. (2003b) • Correlation is not causation. Consider the result within the framework of an specific strength diagnosis.
- 6. Protocol 1. Calibration – force only 2. Zero the force 3. Select the athlete 4. Set the collection period – 10-15s 5. Calculate based on force only 6. Set athlete in 2nd pull position on the plate 7. Lifting straps or chalk 8. Cue appropriately for the data you want 9. 3 minute rest between trials
- 8. Calibration
- 10. Set Position - Joint Angles Hip angle= 155-165 degrees Knee angle = 125-135 degrees
- 11. Set Position - Joint Angles Rower – Possibly a similar build to fast bowlers?
- 12. Set Position - Joint Angles
- 13. Cueing - Force or RFD? Julian Wruck Isometric Force Assessment 13/09/2013 Intention Peak Force (N) Max Rate of Force Development (N/S/S) IMTP Peak Force 7506.3 10177 IMTP RFD 6999.2 30011 • Cue and coach for the data that you want • Rate of force development – “Pull as hard and as fast as you can!” • Peak Force – “Gradually build up to a maximum” • Common Cue – “Drive your feet into the ground and pull the bar from the floor” “push the ground away”
- 14. Analysis of Data • Peak force – N • Relative peak force • Maximum rate of force development • Impulse (force x time) at predetermined time points – Area under the curve
- 15. mRFD Peak force
- 16. Analysis of Data • Peak Force – N – Well correlated with 1RM data • McGuigan and Winchester (2008) – Maximal strength has clearly been shown as a prerequisite for superior performance in tests of muscular power and adaptation to power training • Cormie et al. (2011a, 2011b) • Relative Peak Force • =Peak Force (N) / (Bodyweight (kg) * 9.81) • Or more simply = Peak Force (N) / bodyweight (kg)
- 17. Analysis of Data • Peak Force – N • Relative Peak Force • =Peak Force (N) / (Bodyweight (kg) * 9.81)
- 19. Analysis of Data • Maximum rate of force development (mRFD) – Unreliable without a 1000hz plate and specially designed testing rack. Reduced noise. – Greatest change in force between two data points – However still important due to the influence on performance and injury • Impulse at 100, 200 and 300ms – Force x time – Possibly more reliable but early days in terms of research.
- 21. Real change or typical error? • Figure out the standard deviation for your squad or team. • If the change is > the standard deviation we can safely assume a real change So many variables effect performance that it is incredibly difficult to determine whether or not the intervention has created a real effect but over an extended period of time we want to see a positive trend in scores.
- 22. More to Performance than just Max Strength • World class female sprinter – Peak Force = 2375.32 N – Rel. Peak Force = 3.81 Athletes play to their personal strengths. While max strength is important do not forget reactive, eccentric and dynamic strength qualities. IMTP is well correlated with dynamic performance but correlation is not causation.
- 23. Specific Strength Diagnosis • Volleyball – IMTP, squat jump (EUR) and a power profile with variable loads • Diving – IMTP and a reactive strength profile • Golf – IMTP and specific movement screening
- 24. Acknowledgements • Dr Jeremy Sheppard • Dr Gregory Haff • Further reading – Physiological Tests for Elite Athletes: 2nd Edition • AIS Publication with an outstanding list of expert authors across a range of fields. Thanks for listening! David.Watts@nprsr.qld.gov.au @davewattsau