Isokinetic movement is movement against resistance at a constant speed. It is one method of assessing maximum strength and is widely used in medical and scientific research, both as measurements of strength and a strength training tool. Clinically it is often used to assess strength in particular muscle groups pre and post-operatively.

How does it work?

The Cybex machine offers four types of resistance/movement and three contraction cycle types with numerous feedback options. Common testing formats include comparison of strength in muscle groups between left and right sides, or between agonist and antagonist muscle pairing on the same side.

Resistance can be applied to measure strength during different types of muscle contractions e.g. concentric or eccentric. Results can show if there is an imbalance between sides/muscle groups and can also indicate pathology.

Who would benefit from testing?

Anyone who suspects they may be symptomatic due to poor strength or muscle imbalance may benefit from isokinetic strength testing. Isokinetic is considered the gold standard test for muscle strength post-surgery. Other common reasons for testing are


  • Ligament deficient – conservative management/prehab prior to operation
  • Post-operatively to monitor/assess muscle strength for return to sport/activity
  • Unspecified knee pain


  • Suspected rotator cuff impairment
  • Shoulder surgery – to monitor/assess muscle strength for return to sport/activity


  • Recurrent ankle sprains – assess strength of stabilisers

How long does it take to get results?

Results are produced immediately by the computer. These will be interpreted by the physiotherapist undertaking the testing. 

How are the results used clinically?

Results can highlight weaknesses in a specific muscle group, or across several muscle groups, on side compared to the other. This can help focus strength training to those specific areas of weakness (both muscle group and contraction type) and help guide both the patient and the therapist to achieve optimal outcomes from rehabilitation.

It can also be used to monitor progress and motivate the patient during prolonged rehabilitation. 


Why choose Spire?

We are committed to delivering excellent individual care and customer service across our network of hospitals, clinics and specialist care centres around the UK. Our dedicated and highly trained team aim to achieve consistently excellent results. For us it's more than just treating patients, it's about looking after people.

How much does it cost?

Initial assessment £50.00