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Strength and Muscle Balance Checks

Brian Mackenzie provides advice on how to test your strength and muscle balance.

A speed-strength imbalance between two opposing muscle groups may be a limiting factor in the development of speed. Muscle balance testing to compare the strength of opposing muscle groups is vital to prevent injury and guarantee the maximum speed of muscle contraction and relaxation. Muscle imbalance can slow you down and result in injury.

Strength Checks

Leg press/body weight ratio

Your leg strength/body weight ratio indicates how easily you can get and keep your body moving at high speeds. This ratio is important to speed improvements in short distances. A good ratio is 2.5:1 or a leg press score two and a half times your body weight. If it is less than 2.5, then you should consider modifying the programme to develop leg strength.

Leg strength test

The squat is considered the most functional leg strength test in predicting sprinting and jumping ability. Good 1RM (one rep max) scores are:

  • Male athletes 2 x "Body Weight"
  • Female athletes 1.5 x "Body Weight"

Hamstring/Quadriceps strength

For each leg record the 1RM for the leg curl and leg extension exercises. Divide your leg curl score by the leg extension score to find the ratio for each leg. For each leg, the curl score should be at least 80%, of your extension score. If the score is less than 80% then you need to devote more training attention to the hamstrings. To reduce the chance of injury, the ratio should be at least 75%.

Bench Press

This is a test for upper body strength. The need for maximum upper body strength varies between sports, and so it does not always need to be tested for. Good 1RM scores are:

  • Male athletes 1.25 x "Body Weight"
  • Female athletes 0.8 x "Body Weight"

Balance checks

For each of the following exercises, the right and left limb 1RM scores should not differ by more than 10%.

  • Hamstrings (leg extension)
  • Quadriceps (leg curl)
  • Arm Curl
  • One arm military press
  • Single leg press

The following table is reported values for the joint agonist to antagonist ratios at slow isokinetic speeds.

Joint Movement Ratio
Ankle Plantar flexion/dorsiflexion 3:1
Ankle Inversion/Eversion 1:1
Leg Extension/flexion 3:2
Hip Extension/flexion 1:1
Shoulder Flexion/extension 2:3
Elbow Flexion/extension 1:1
Lumbar Flexion/extension 1:1

Where there is an imbalance, then you need to devote more training attention to the muscle group of the weaker limb.

Article Reference

This article first appeared in:

  • MACKENZIE, B. (2003) Strength and Muscle Balance Checks. Brian Mackenzie's Successful Coaching, (ISSN 1745-7513/ 7 / November), p. 7

Page Reference

If you quote information from this page in your work, then the reference for this page is:

  • MACKENZIE, B. (2003) Strength and Muscle Balance Checks [WWW] Available from: [Accessed

About the Author

Brian Mackenzie is a British Athletics level 4 performance coach and a coach tutor/assessor. He has been coaching sprint, middle distance and combined event athletes for the past 30+ years and has 45+ years of experience as an endurance athlete.