The Fundamentals of Building Muscle after Knee Surgery

Feb 20, 2023

After sustaining a knee injury or undergoing knee surgery you will notice that the quadriceps (muscle group at the front of your thigh) loses muscle bulk and strength quite quickly. Regaining function, strength and bulk of the quadriceps is the primary goal of your rehabilitation.

Reconstructive procedures such as ACL reconstruction, patella stabilisations, OATS procedures and ligament reconstructions (LCL/MCL) usually require 4-6 months of strength work before the quadriceps strength and bulk returns to within normal parameters. We usually test the strength of the quadriceps using isokinetic testing at approximately 4 months after reconstructive surgery. Building muscle bulk and strength can be challenging and there are a number of variables which contribute to it’s success which we have discussed below.

Exercise Programme

The quality of your exercise programme following knee surgery is critical. We have put together a number of tips to help you make the most of this:

– Aim for 2-3 lower limb hypertrophy (growth) focused gym sessions per week. You should have rest days between your leg sessions, recovery is essential for muscle growth!
– Lift heavy enough (75-85% of 1RM)! Aim for fatigue between 6-12 reps ie. If you can do 16 reps the weight is too light.
– Rest: Aim for 3 sets of 6-12 reps allowing for rest periods of 60-90 seconds between each set.
– Be Smart with Exercise Selection: A mix of Leg Press (our favourite for quad building), high step ups, lunges, squats, hip thrusts, RDLs and leg extensions (late stages for ACL/patellar tendon procedures) should be included. A single leg focus should be introduced after 4-6 weeks of performing double leg exercises.
– Don’t spend 2 hours in the gym: 45 minutes of a leg session (if done correctly) is plenty. Aim for 5-7 exercises and focus on maximising effort on these.
– Keep it varied: It is a good idea to have a ‘bank’ of exercises and mix-match these for your sessions to keep it varied. Weights should be increased regularly as muscles adapt quickly to exercise and you need to continuously challenge them to stimulate growth!


Building muscle is not all about the work you put in at the gym. Optimising your nutrition to support muscle building will fast track your results!
The Importance of Nutrition when trying to build Muscle:
Protein is the most important nutrient for building and repair of muscle. Research suggests that athletes should be aiming for 1.2-2g protein per kg of body weight. Lean meat, fish, eggs, chicken, turkey are good protein sources, you can also supplement with a protein power.
Carbohydrates are also critically important for muscle growth. Carbohydrate intake guidelines depend on activity. For those participating in exercise ie gym session for 1 hour a day 5-7g per kg of body weight is recommended.
Creatine is probably the most evidenced based supplement available. Supplementation with creatine can increase strength and performance by up to 15% and also has been shown to reduce fatigue. 3-5g per day is recommended as a daily dose.


Sleep is often the forgotten secret weapon to building strength. Muscle growth happens when we rest therefore sleep is crucially important for muscle recovery, particularly when recovering from your Knee Surgery.

Tips for good sleep hygiene:
– Aim for 8-9 hours each night.
– Set a consistent sleep & bedtime routine
– Limit caffeine to morning time.
– Limit screen time before you go to bed
– Create a relaxing environment (dim lights etc)
– Keep the room cool and dark
– Try meditation or relaxation apps if you have difficult falling asleep.

If you need more information on what to do after your Knee Surgery, check out the Knee section of our website. You can also get in touch with our team by emailing [email protected]

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• Ralf Jäger, Chad M. Kerksick, Bill I. Campbell, Paul J. Cribb, Shawn D. Wells, Tim M. Skwiat, Martin Purpura, Tim N. Ziegenfuss, Arny A. Ferrando, Shawn M. Arent, Abbie E. Smith-Ryan, Jeffrey R. Stout, Paul J. Arciero, Michael J. Ormsbee, Lem W. Taylor, Colin D. Wilborn, Doug S. Kalman, Richard B. Kreider, Darryn S. Willoughby, Jay R. Hoffman, Jamie L. Krzykowski & Jose Antonio (2017) International Society of Sports Nutrition Position Stand: protein and exercise, Journal of the International Society of Sports Nutrition, 14:1, DOI: 10.1186/s12970-017-0177-8