Stretch marks (striae) in athletes: causes and the link to training load and pharmacology
Stretch marks on the shoulders, chest and thighs are one of the most common complaints among people who do strength sports. Some consider them an inevitable price for muscle, others a sign of 'chemistry.' The editorial team looked into what actually happens to the skin, which training-load and pharmacological factors are linked to striae, and when stretch marks should be treated as a signal to check your health.
What striae are from a dermatological standpoint
Stretch marks, or striae (Lat.striae distensae), are linear atrophic scars of the skin that form when the dermis fails to adapt to stretching in time or loses its mechanical strength for other reasons. Unlike superficial scratches, the damage occurs deep down: in the reticular layer of the dermis, where collagen and elastic fibers are located. That is why striae cannot be 'washed off' with a cream and remain on the skin for years, although they become less noticeable over time.
Dermatologists distinguish two stages. Fresh striae (striae rubrae) are pink, red or purple, sometimes slightly raised above the surface and itchy. Their color is explained by inflammation and dilation of blood vessels. Mature striae (striae albae) are whitish, silvery, sunken, with a thin wrinkled surface; scar tissue with disorganized fibers has already formed in them.
Histological studies have shown that in striae areas the number of fibrillin microfibrils and elastic fibers decreases, and collagen bundles are arranged parallel to the skin surface, as if 'stretched' in one direction (Watson et al., 1998). This explains why the skin in these places is thinner, softer to the touch and recovers worse.
Striae are not dangerous in themselves, but they can be a marker of processes worth evaluating: a sharp gain in mass, hormonal changes, the effect of drugs. That is why, for an athlete, the appearance of stretch marks is a reason not only for cosmetic reflection but also for analyzing one's own regimen and pharmacological background.
The mechanical factor: rapid growth of muscle and body mass
The main 'sports' cause of striae is a mismatch between the rate at which tissue volume increases and the skin's ability to adapt. The skin is able to stretch, but its remodeling happens gradually. When the volume of muscle or fat tissue grows faster than fibroblasts can synthesize new collagen and elastin, microtears appear in the dermis and later scar over.
In strength sports the most typical zones are the front of the shoulder near the armpit (the border of the deltoid and pectoralis major), the chest, biceps, thighs and lower back. It is precisely here that intense hypertrophy combines with constant changes in skin tension during movement. Among bodybuilders, striae in the armpit area are so widespread that they are often perceived as a 'badge of the trade,' although in fact they are a sign of gaining too quickly.
The second mechanical scenario is aggressive 'mass-gaining' phases with a large calorie surplus. When body mass grows by many kilograms over a few months, a significant share of the gain is fat, and stretch marks appear on the abdomen, sides, buttocks and thighs. A similar picture is seen in adolescents during a growth spurt: then striae appear even without training.
It is important that training load as such does not harm the skin. Gradual hypertrophy against a background of a moderate energy surplus is mostly not accompanied by striae, or gives only isolated thin lines. The problem arises when the rate of change becomes extreme, whether naturally or through pharmacology.
- rapid gain in body mass (mass gain, return after a diet);
- intense hypertrophy of the shoulder girdle and thighs;
- a period of active growth in adolescence;
- skin changes under the influence of hormones or medications;
- hereditary predisposition and connective-tissue features.
Hormones and pharmacology: what worsens skin condition
The second large group of causes is endocrine. The best-proven link is between striae and glucocorticoids. Cortisol and its synthetic analogues suppress fibroblast proliferation and collagen synthesis and thin the dermis. Wide crimson striae on the abdomen are a classic sign of Cushing's syndrome, and endocrinology guidelines list them among the symptoms that increase the likelihood of this diagnosis (Nieman et al., 2008).
For athletes this has practical significance: prolonged systemic treatment with corticosteroids (for example, for injuries, asthma or autoimmune conditions) and even excessive use of strong topical steroid ointments on one area can cause striae. Such stretch marks are often wider, brighter and located atypically.
Anabolic-androgenic steroids are mentioned in an Endocrine Society review among the causes of dermatological changes, and striae are among the frequent cosmetic consequences of their use (Pope et al., 2014). The mechanism is combined: a sharp gain in muscle mass and water-salt shifts increase the mechanical load on the skin. In addition, accompanying drugs, in particular growth hormone and insulin, which accelerate changes in tissue volume, affect the skin.
Separately, it is worth mentioning genetic connective-tissue disorders (for example, Marfan or Ehlers-Danlos syndrome), in which striae can appear without visible load. In such cases stretch marks are only one of the signals, alongside joint hypermobility and features of vision or the cardiovascular system.
| Factor | How it affects the dermis | Typical localization of striae |
|---|---|---|
| Rapid muscle hypertrophy | Mechanical overstretching, microtears of fibers | Armpit area, chest, biceps |
| Sharp gain in fat mass | Increase in the volume of subcutaneous fat | Abdomen, sides, thighs, buttocks |
| Glucocorticoids | Suppression of fibroblasts and collagen synthesis | Abdomen, thighs, wide crimson lines |
| Anabolic steroids and accompanying hormones | Rapid change in tissue volume, water shifts | Shoulder girdle, chest |
| Hereditary connective-tissue disorders | Reduced strength of elastic structures | Varied, often with no obvious cause |
Who is in the risk group
Susceptibility to striae is largely determined by genetics. The systematic review by Al-Himdani et al. (2014) names family history, young age at sharp changes in body mass and skin characteristics among the risk factors. If close relatives had pronounced stretch marks during pregnancy or growth, the likelihood of their appearance in an athlete is higher.
Age also matters. In adolescents and young athletes the skin grows actively, and the combination of a natural growth spurt with the start of strength training sometimes produces noticeable striae on the back, thighs and shoulders. At an older age regeneration is slower, so the skin adapts worse to a sharp gain in mass.
Disciplinary features are also significant. The highest risk is in bodybuilding, powerlifting in heavy categories, throwing events and contact sports where athletes 'move up a category.' The lowest is in endurance sports, where body mass is stable.
Finally, the risk group includes those who use hormonal drugs or receive prolonged corticosteroid treatment for medical indications. For this group, the appearance of striae is a reason to review the overall plan with a doctor rather than simply pick out a cream.
What can be changed in training and nutrition
Since the speed of change is the key mechanical factor, the most effective thing an athlete can do is to control the rate of gain. A moderate calorie surplus and gradual weight gain reduce the load on the skin and at the same time reduce the share of fat in the gained mass. This is beneficial both for aesthetics and for health.
Training planning also matters. A sharp transition to a large volume of chest and shoulder work after a break, especially combined with a sharp increase in calories, creates 'ideal' conditions for striae to appear in the armpit area. A gradual buildup of volume helps not only the muscles and tendons but also the skin.
Nutrition should provide enough protein, vitamin C, zinc and other nutrients needed for collagen synthesis. However, it is worth saying honestly: there is no convincing evidence that any supplement prevents striae. Nutrients only support normal tissue-recovery processes but do not compensate for an excessive rate of gain.
On pharmacology the editorial position is unambiguous: the appearance of striae against a background of hormonal drugs is a risk signal, not a cosmetic trifle. It indicates overly rapid changes in the body and is often accompanied by other, less noticeable consequences: changes in the lipid profile, blood pressure, hematocrit. These indicators should be checked together with a doctor.
For more detail on prevention, diagnosis and treatment methods, read our separate article on striae in athletes. Our materials on the correct rate of mass gain, on the risks of corticosteroid therapy for athletes and on the side effects of anabolic steroids will also be useful.
Editorial conclusions
Striae in athletes are scarring changes of the dermis that occur when the skin fails to keep up with changes in body volume or loses strength under the influence of hormones. The most common causes are rapid mass gain, intense hypertrophy of the shoulder girdle, genetic predisposition and the action of glucocorticoids.
Anabolic steroids and other hormonal drugs increase the risk of striae indirectly, through sharp changes in body mass and tissue volume. The appearance of stretch marks against such a background should become a reason to assess overall health.
The best prevention is gradual, controlled progress. If striae are wide, crimson, appear without an obvious cause or are accompanied by other symptoms (weight gain on the trunk, weakness, elevated blood pressure), see a doctor to rule out endocrine disorders.
References
- Al-Himdani S, Ud-Din S, Gilmore S, Bayat A. Striae distensae: a comprehensive review and evidence-based evaluation of prophylaxis and treatment. Br J Dermatol. 2014;170(3):527–547.
- Elsaie ML, Baumann LS, Elsaaiee LT. Striae distensae (stretch marks) and different modalities of therapy: an update. Dermatol Surg. 2009;35(4):563–573.
- Watson RE, Parry EJ, Humphries JD, et al. Fibrillin microfibrils are reduced in skin exhibiting striae distensae. Br J Dermatol. 1998;138(6):931–937.
- Nieman LK, Biller BM, Findling JW, et al. The diagnosis of Cushing's syndrome: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab. 2008;93(5):1526–1540.
- Pope HG Jr, Wood RI, Rogol A, et al. Adverse health consequences of performance-enhancing drugs: an Endocrine Society scientific statement. Endocr Rev. 2014;35(3):341–375.
- Ud-Din S, McGeorge D, Bayat A. Topical management of striae distensae (stretch marks): prevention and therapy of striae rubrae and albae. J Eur Acad Dermatol Venereol. 2016;30(2):211–222.
Andriy Melnyk
A strength-sports coach and author of programs for beginner and intermediate levels. Writes about training planning.
