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Nutrition for ACL Rehabilitation
A phase-matched framework. A loss of quadriceps muscle mass is common after ACL injury — the right nutrition, timed and dosed to match each stage of rehab, can limit that deterioration and support muscle rebuilding before and after reconstruction.
Enquire NowAfter an ACL injury, the quadriceps can waste away quickly due to muscle disuse. This loss of muscle mass can be persistent and carries long-term consequences including:
- Accelerated deterioration of knee joint cartilage
- Reduced lower limb strength
- Poor knee joint health
The nutritional strategies below have been shown to limit muscle deterioration and aid hypertrophy before reconstruction and during the stages of rehabilitation. Rather than a blanket "post-op supplement" approach, nutrition should be timed and dosed to match the individual's current rehab phase and tissue tolerance.
Disclaimer: This article is for general information only and isn't a substitute for personalised advice. Always consult your physiotherapist, surgeon or a registered nutritionist before starting supplements.
Nutritional Foundations
Get the basics right first — energy, carbohydrate and protein are the foundation that every supplement sits on top of.
Energy Availability
Now is not the time to try to "lose weight". Activity levels may have dropped, but healing keeps energy demands high. Even a 20% energy deficit can lead to a 16% reduction in muscle protein synthesis. Once resting metabolic rate (RMR) and overall activity are accounted for, the stress of ACL reconstruction surgery further increases energy needs.
Carbohydrate Availability
Adequate carbohydrate supports training quality and amino acid availability. Restricting carbohydrate has been shown to blunt muscle hypertrophy — which is counterproductive during rehab.
Protein & Essential Amino Acids
Protein is the primary stimulator of muscle protein synthesis. Food sources should come first, with additional isolated supplements (e.g. whey) considered alongside.
- General athletic guidance: approx. 2 g/kg/day to support repair and remodelling
- 20–40 g (age dependant) of high-quality protein after rehab exercise to maximise the synthetic response
- Leucine content and timing/spread across the day matter, particularly with low energy intake or anabolic resistance
Key Supplements
Supplements complement — they never replace — good food choices and a well-structured rehab programme.
Creatine
Most useful once resistance training intensity increases (mid-to-late phase), though preoperative/early loading protocols have also shown preserved muscle mass in disuse models.
Dosage: 20 g/day for five days, followed by incrementally smaller doses of 15 g/day (weeks 1–3) and 5 g/day (weeks 4–10).
Omega-3 Fatty Acids
An anti-inflammatory that could help to stimulate muscle protein synthesis and may attenuate muscle atrophy.
Dosage: 2–5 g/day of combined EPA/DHA.
Collagen (Peptides/Gelatine)
Rich in glycine and proline — key substrates for the collagen-rich tensile element of tendons and ligaments. Note: collagen does not replace whey protein, which performs better at stimulating muscle protein synthesis.
Dosage: 15 g with vitamin C, taken prior to rehabilitation exercises. Sources should be bovine, porcine, marine or poultry hydrolysed collagen.
Caffeine
A central nervous system stimulant allowing individuals to train harder during late-stage high-load/power phases.
Food First: The Recovery Plate
Every nutrient in this guide starts on the plate — tap any photo to take a closer look at the foods behind the framework.
Implementation Across Phases of ACL Rehab
How the nutritional supports change across the phases of rehabilitation training — matching supplementation goals to each stage may enhance patient outcomes (Fig 1).
| Phase | Nutritional Supports & Supplements |
|---|---|
| Pre-Operative Phase (~2–4 weeks pre-op) |
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| Early Rehab Phase (2 wks – 3 months) |
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| Mid-Stage Rehab (3 – 6 months) |
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| Late-Stage (6 – 9+ months) |
|
References
- Lee, E. J., & Kim, J. (2026). Rehabilitation Nutrition for Tendon and Ligament Injuries: From Collagen Remodeling to Return-to-Activity and Sport. Healthcare (Switzerland), 14(14).
- Smith, M. J., Hoffman, N. J., Jose, A. J. S., Burke, L. M., & Opar, D. A. (2025). Nutritional Interventions to Attenuate Quadriceps Muscle Deficits following Anterior Cruciate Ligament Injury and Reconstruction. Sports Medicine, 55(3), 569–596.
- Smith-Ryan, A. E., Hirsch, K. R., Saylor, H. E., Gould, L. M., & Blue, M. N. M. (2020). Nutritional considerations and strategies to facilitate injury recovery and rehabilitation. Journal of Athletic Training, 55(9), 918–930.
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