Protocols General

An initial warm up, including stretching and gentle cardiovascular work, should be performed for 15 minutes prior to the use of the isokinetic machine. The only exception to this is in the case of research which specifically targets sports which would not normally involve a warm up period.

Familiarization

Isokinetic exercise is not easy to become familiar with (try it yourself). So it is vital that a detailed description of what will be required of the subject is given, this should be followed by a period of 'test' sub-maximal contractions (assistance by the machine using passive or active assisted modes is acceptable). If eccentric motions are to be used then the subject should be comfortable with the motion before testing and they should be warned to expect some delayed onset of muscle soreness (DOMS) although my subjects/patients rarely complain of this. For research purposes familiarization should occur on a separate day to testing.

Type of Contraction

Reciprocal (con/con and ecc/ecc) or absolute (con/ecc).

Reciprocal - good for patients (con/con)

High correlation of power and work findings makes it good for research.

Absolute - good for average strength

The effects of isometric pre-activation (plyometrics) will not necessarily adversely affect results (Dvir 1995) and may be of interest to researchers examining high level performers.

Test Velocities

Lower velocities show lower variation

Higher velocities (above 180 degrees/second) show higher variation.

Starting low and working up gives better correlation.

Starting high and working down is easier for patients.

Random velocities for research.

Warm up repetitions

Specific for type of activity see individual joints.

Number of Repetitions

Specific for type of activity see overview table or individual joints.

Number of Sets

Specific for type of activity see overview table or individual joints.

Rest

Rest between individual repetitions

A 20 second rest between each repetition has been shown to allow increases which do not appear to plateau until fatigue (Dvir 1995). A 1 second pause between con/ecc contractions reduces the effects of the isometric pre-activation (particularly at high speeds) but this may be of interest to researchers

Rest between individual sets

30 - 60 seconds for peak torque and over 1 minute for endurance

Between speeds

1 minute

Between sides

3 - 5 minutes should be waited before testing the contra lateral side

Between joints

Chan and Maffulli (1996) recommend at least one days rest before testing another joint in the same limb e.g. ankle and knee

Warm down

A 15 minute warm down should be undertaken immediately following isokinetic exercise. This should include both stretches and gentle cardiovascular work.

Repeated Measures

Differences between sessions

Johnson and Siegel (1978) examined the reproducibility of uni-directional movement in 40 normal women. They concluded that over 6 days each of the subjects got better results. Chan and Maffulli (1996) recommend an initial test followed by a subsequent test 2 days later with the second test used as the criterion for improvement monitoring

Differences between repetitions

Correlation of repeated repetitions can be used to determine intra-subject motivation e.g. compliance test for (often used for functional capacity evaluations FCE)