Elite athletic preparation is a fine balance between pushing the training and adaptation boundaries for performance, and avoiding injury, illness, or physical and mental fatigue which result in underperformance. (Halson S. 2014; Saw et al. 2018; Etxebarria et al 2019)
Nutrition is an important part of the preparation (training phase) of performance and any athlete’s diet. High quality nutrition will not only ensure that the body is fuelled correctly for training, but it will also support recovery and the necessary physiological adaptations required for sport participation, both of which are paramount to both injury prevention and performance (Tiller et al 2019).
Dietary protein has been singled out as one of the most important macronutrients for athletic performance. Muscles, bones, and connective tissues require protein to repair and adapt to training. One of the most important and abundant structural proteins in the body is collagen.
Collagen plays an important structural role for bone, connective tissues and muscle, and is the main component of the extracellular matrix (ECM). The extracellular matrix is a three-dimensional scaffolding of large molecules collagen, glycosaminoglycans, proteoglycans and glycoproteins that provide structural and biochemical support to cells and tissues in the human body. In the presence of a nutritional insufficiency, or a disease state, a poor extracellular matrix is produced in our tissues that is unable to withstand the mechanical demands of normal activity (Kip 1996).
Collagen production is affected by age. From the mid-twenties, collagen production starts to decline. Age-related changes to the collagen proteins in the extracellular matrix (ECM) have far reaching consequences, with the potential to disrupt many different aspects of healthy function (Birch 2019). Clinically, elite athletes tend to become more susceptible to certain injuries or experience longer recovery/return to competition times after injuries from their late twenties to the early thirty age group.
In recent years, there has been a growing interest in the use of protein supplements derived from collagen. These products contain collagen-specific peptides, or gelatin (partially hydrolysed collagen). More specifically, they are derived from the connective tissue of animals and contain high amounts of the collagen- specific amino acids (AA) hydroxyproline, glycine and proline that, together, comprise almost two-thirds of the total amino acids in collagen (Li and Wu 2018). This interest stemmed from a research study published in the American Journal of Clinical Nutrition (Shaw et al 2017) demonstrating that ingesting 5 – 15 g of collagen peptides, in the form of gelatin, can augment collagen synthesis, specifically the collagen found in ligaments. These results were of high clinical interest as collagen peptides demonstrate a high absorption rate and availability to tissues for biological functions (Ohara et al. 2007; Shaw et al. 2016)
Collagen Components of Muscle and Tendon and its Significance For Repair and Performance
Research has traditionally focused on the physiological effects of exercise on skeletal muscle fibres themselves. More recently, however, studies have demonstrated that exercise can also modify the proteins surrounding the muscle fibres in the extracellular matrix (Clarkson and Sayers,1999)
A growing body of evidence supports the significance of the ECM in maintaining normal muscle function and its ability to adapt to a given stimulus (Gillies and Lieber 2011). The ECM’S complex scaffolding maintains structural integrity and transmits forces across muscle fibres within the muscle myofibrils. More specifically, researchers have found that the ECM has an important role in the transition of muscle force during contractions (e.g., exercise) and reparative and remodelling processes following exercise (MacKay and Kjar 2016)
Research studies have shown that exercise rapidly increases collagen protein synthesis, suggesting that the ECM can adapt even from one training session. (Hans 1999, MacKay and Milliner). Others have also reported indirect evidence of collagen breakdown after strenuous exercise. Indeed, several studies (Brown et al. 1999; Tofas et al. 2008) have seen marked increases in collagen-specific amino acids in the circulation in the days following exercise, suggesting that the ECM is damaged and/or remodelled following exercise. The consequence of such damage is likely to be a sub-optimal distribution of myofibrillar forces throughout the muscle fibre, which, in turn, might reduce muscle contractile function.
This led researchers to explore the effect of supplementing with collagen-specific peptides to help attenuate any of the negative symptoms associated with muscle damaging exercise, typically, depressed muscle force production and muscle soreness. In a recent study, (Clifford et al 2019), found that ingesting collagen peptides for 7 days prior and for 2 days after strenuous muscle damaging exercise, could reduce feelings of muscle soreness more effectively than a placebo control.
Animal studies looking at the Achilles tendon specifically found that ingestion of collagen peptide affects the size of collagen fibrils and composition of glycosaminoglycans in the Achilles tendon which could lead to improvements in the mechanical properties of the Achilles tendon (Minaguchi et al 2005). A study published in Nutrients (Praet et al 2019) found that combining calf strengthening exercises with supplements of collagen peptides reduced pan and improved function in established Achilles tendinopathy patients an encouraging starting point to establish future research in degenerative soft tissue conditions.
Collagen Component of Joint Articular Cartilage and its Significance For Repair
Articular cartilage is highly specialised in its biological function and mechanical properties to sustain the load that we confer on our joints. It’s ability to perform these functions depends on the composition of its ECM. ECM composition, integrity, and synthesis depends on the cartilage cell (Muir 1995). It is the chondrocytes that are responsible for continuous remodelling of ECM components that respond to ECM changes by synthesizing new macromolecules (Buckwalter and Mankin 1998). If there is a progressive imbalance between ECM degradation and regeneration, there is a marked decrease in type II collagen content in ECM and this eventually results in cartilage damage (Mlynarik and Trotting 2000).
It is well established that athletes are at increased risk cartilage damage developing joint lesions. (Lequesne et al 1997, Schueller-Weidekamm et al 2006). Joint lesions are interruptions in the naturally smooth cartilage lining that covers the joints. Where this lining is damaged by other fracture or tear the function of the joint suffers and may be associated with pain and disability. There is a strong correlation between joint cartilage lesions and subsequent development of osteoarthritis and its progression (Buckwalter J 2002).
The level of athleticism matters. Regular joint loading may be protective with current evidence supporting that running in lower doses may be protective against development of osteoarthritis (Kenyon 2020). In fact, in those with a sedentary lifestyle, the loading experienced from single marathon may improve appearances of damaged subchondral bone when considering the tibial and femoral condyles of the knee (Horga 2019). However, studies show an increased prevalence of knee OA in professional athletes compared to general population or non-professional athletes. (Papalia R, Torre G, Zampona et al 2019) In football the risk for professional (soccer) to develop arthritis in at least one lower extremity joint is significantly higher than that of the general population (Drawer S, Fuller C 2001). Although it is important to consider the traumatic, high impact, elements of elite sports participation with associated ligament and acute joint injury considerations.
A study that investigated the effect of degraded collagen on the formation of type II collagen by mature bovine chondrocytes in a cell culture model found increased type II collagen biosynthesis. The presence of extracellular collagen hydrolysate (CH) led to a dose- dependent increase in type II collagen secretion (Oesser et al 2003) supporting later findings that it was readily absorbed across the gastro- intestinal mucosa in mice and distributed to hyaline cartilage, where it accumulates (Oesser 1999). This supports higher doses of collagen ingestion may be beneficial to support cartilage health.
Other clinical studies support the beneficial effects of collagen peptides on joint health. In two studies, ingestion of collagen peptides led to reductions in self-reported joint pain in physically active young males and females (Clark et al. 2008; Zdzieblik et al. 2017). In clinical populations, for example those suffering from joint diseases such as osteoarthritis, several studies have reported that collagen peptide ingestion reduces muscle and joint pain (Kumar et al. 2015; Flechsenhar and McAlindon 2016; Woo et al. 2017).
Is a Well-Balanced Diet Not Enough?
Added to the natural collagen production decline associated with age emerging research tells us that natural dietary intake may not be enough. Alcock et al (2019) demonstrated that bone broth (a naturally collagen-rich food source in the human diet) is unlikely to provide reliable concentrations of collagen precursors compared to supplement doses used in research.
Additionally, athletes may find sustaining a well-balanced diet challenging, especially as their training loads are starting to push personal boundaries. Perception of diet and food ingested may be altered. Prolonged endurance exercise is associated with changes in food/fluid palatability (Tiller et al 2019). A study looking at marathon runners exposed to changing environmental found rising temperature inhibited appetite and the desire to eat (Allison et 2009). Travel and competition schedules may also have an impact.
Preserving Health and Wellbeing and Optimizing Performance in The Athlete
There are many factors that can influence an athlete’s susceptibility to injury and in elite sport we carefully consider the athletes training load and intensity, the injury history their individual exposure and reactions to differing environmental stresses, even their genetic predisposition but it is imperative that we as clinicians are actively seeking to find novel and effective prevention strategies to avoid injury and prolong careers.
There is a need for larger clinical, longer term studies particularly on the use of higher doses of collagen and its effect on degenerative joint conditions, soft tissue repair, injury prevention and performance. However, there are no reported adverse effects of collagen supplementation particularly if ingested with food. Our digestive system recognises collagen hydrolysate as containing the necessary composite building blocks that maintain the integrity of its tissues. Optimising nutrition with oral collagen supplementation at a time of injury or high physical stress with increasing training loads and demand would be advisable. It is important to remember that current levels of evidence support a dose dependent effect so opting for higher dosages in the choice of collagen supplements is significant.
Alcock, R. D., Shaw, G. C., & Burke, L. M. (2019). Bone Broth Unlikely to Provide Reliable Concentrations of Collagen Precursors Compared with Supplemental Sources of Collagen Used in Collagen Research. International Journal of Sport Nutrition and Exercise Metabolism, 29(3), 265-272.
Allison L Shorten, Karen E Wallman, Kym J Guelfi. Acute effect of environmental temperature during exercise on subsequent energy intake in active men, The American Journal of Clinical Nutrition, Volume 90, Issue 5, November 2009, Pages 1215–1221,
Birch 2019 Biochemistry and Cell Biology of Ageing: Part I Biomedical Science pp 169-190 Springer 2019
Buckwalter JA, Mankin HJ (1998) Articular cartilage: degeneration and osteoarthritis, repair, regeneration, and transplantation. Instr Course Lect 47:487–504
Buckwalter J (2002) Articular Cartilage Injuries. Clin Orthop Relat Res. Sep;(402):21-37.
Clarkson PM, Sayers SP (1999) Etiology of exercise-induced muscle damage. Can J Appl Physiol 24(3):234–248
Crameri RM, Aagaard P, Qvortrup K, Langberg H, Olesen J, Kjær M (2007) Myofibre damage in human skeletal muscle: effects of electrical stimulation versus voluntary contraction. J Physiol 583(1):365–380
Drawer S, Fuller CW. Propensity for osteoarthritis and lower limb joint pain in retired professional soccer players. British Journal of Sports Medicine 2001; 35:402-408.
Drew M.K., Raysmith B.P., Charlton P.C. Injuries impair the chance of successful performance by sportspeople: A systematic review. Br. J. Sports Med. 2017; 51:1209–1214. doi: 10.1136/bjsports-2016-096731.
Etxebarria N, Mujika I, Pyne D. Training and Competition Readiness in Triathlon: Sports (Basel). 2019 May; 7(5): 101.
Fredericson M (1), Misra AK. Sports Med. 2007;37(4-5):4379. Epidemiology and aetiology of marathon running injuries.
Friedman JE, Lemon PW. Effect of chronic endurance exercise on retention of dietary protein. Int J Sports Med. 1989;10(2):118–23.
Friedman JE, Lemon PW. Effect of chronic endurance exercise on retention of dietary protein. Int J Sports Med 1989Apr:10(2):118-23
Gillies AR, Lieber RL (2011) Structure and function of the skeletal muscle extracellular matrix. Muscle Nerve 44(3):318–331
Halson, S.L. Monitoring training load to understand fatigue in athletes. Sports Med. 2014, 44 (Suppl. 2), S139–S147.
Hyldahl RD, Hubal MJ (2014) Lengthening our perspective: morpho- logical, cellular, and molecular responses to eccentric exercise. Muscle Nerve 49(2):155–170
Horga LM, Henckel J, Fotiadou A, et al. Can marathon running improve knee damage of middle-aged adults? A prospective cohort study
BMJ Open Sport & Exercise Medicine 2019;5: e000586. doi: 10.1136/bmjsem-2019-000586
Kenton D et al. Runner. Assessment, Biomechanical Principles, and Injury Management 2020, Pages 169-180
Lepers R, Cattagni T. Do older athletes reach limits in their performance during marathon running? Age 2012; 34:773–81.
Lequesne MG, Dang N, Lane NE. Sport practice and osteoarthritis of the limbs. Osteoarthritis Cartilage 1997; 5:75–86.
Mackey AL, Kjaer M (2016) Connective tissue regeneration in skeletal muscle after eccentric contraction-induced injury. J Appl Physiol 122(3):533–540
Minaguchi J, Koyama Y, Meguri N, et al. Effects of ingestion of collagen peptide on collagen fibrils and glycosaminoglycans in Achilles tendon. Journal of nutritional science and vitaminology. 2005;51(3):169–174
Muir H (1995) The chondrocyte, architect of cartilage: biomechanics, structure, function and molecular biology of cartilage matrix macromolecules. Bioessays 17:1039–1048
Oesser, S., Seifert, J. Stimulation of type II collagen biosynthesis and secretion in bovine chondrocytes cultured with degraded collagen. Cell Tissue Res 311, 393–399 (2003) doi:10.1007/s00441-003-0702-8
Oesser S, Adam M, Babel W, Seifert J. Oral administration of (14)C labeled gelatin hydrolysate leads to an accumulation of radioactivity in cartilage of mice (C57/BL). J Nutr 1999;129: 1891e5.
Ohara H, Matsumoto H, Ito K, Iwai K, Sato K (2007) Comparison of quantity and structures of hydroxyproline-containing peptides in human blood after oral ingestion of gelatin hydrolysates from different sources. J Agric Food Chem 55(4):1532
Praet SFE, Purdam CR, Welvaert M, et al. Oral Supplementation of Specific Collagen Peptides Combined with Calf-Strengthening Exercises Enhances Function and Reduces Pain in Achilles Tendinopathy Patients. Nutrients. 2019;11(1):76. Published 2019 Jan 2. doi:10.3390/nu11010076
Schueller-Weidekamm, C., Schueller, G., Uffmann, M. et al. Eur Radiol (2006) 16: 2179.
Shaw G, Lee-Barthel A, Ross ML, Wang B, Baar K (2016) Vitamin C–enriched gelatin supplementation before intermittent activity augments collagen synthesis. Am J Clin Nutr 105(1):136–143
Tiller et al. Journal of the International Society of Sports Nutrition (2019) 16:50 Page 3 of 23
Tosch U, Sander B, Schubeus P, Eckart L, Felix R. Magnetic resonance tomographic and sonographic imaging of the ankle in marathon runners. Rofo Fortschr Geb Rontgenstr Neuen Bildgeb Verfahr 1991; 154:150–4.
Zdzieblik D, Oesser S, Gollhofer A, König D (2017) Improvement of activity-related knee joint discomfort following supplemen- tation of specific collagen peptides. Appl Physiol Nutr Metab 42(6):588–595