Overview• Personal experience• Justification for use• Isometric tests and athletic performance• Protocol• Peak Force or Rate of Force Development• Data Analysis• Specific Strength Diagnosis

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.

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)

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.

Protocol1. Calibration – force only2. Zero the force3. Select the athlete4. Set the collection period – 10-15s5. Calculate based on force only6. Set athlete in 2nd pull position on the plate7. Lifting straps or chalk8. Cue appropriately for the data you want9. 3 minute rest between trials

BMS Test Window

Calibration

Zero and Collection Period

Set Position - Joint Angles

Hip angle= 155-165 degrees Knee angle = 125-135 degrees

Set Position - Joint Angles

Rower – Possibly a similar build to fast bowlers?

Set Position - Joint Angles

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 10177IMTP 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”

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

mRFD

Peak force

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)

Analysis of Data• Peak Force – N• Relative Peak Force

• =Peak Force (N) / (Bodyweight (kg) * 9.81)

Peak Force Normative Data

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.

mRFD Normative Data

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.

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.

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

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