Spondylolysis: a spinal stress fracture commonly missed in young athletes

myBackPain Assessment

Back pain in a young or active person that isn’t settling?

The myBackPain assessment identifies the spondylolysis pattern — extension aggravation, sport participation, and failure to settle as expected — and guides the right next steps. Results in minutes.

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30–55%

of elite fast bowlers have spondylolysis — the highest rate of any sport

of the general population have spondylolysis — many without knowing

Missed

on standard X-ray in up to 30% of cases — MRI or CT required for definitive diagnosis

What is spondylolysis?

Spondylolysis is a stress fracture or defect in the pars interarticularis — a small bony bridge in the vertebra connecting the upper and lower joint surfaces at the back. It is one of the most commonly missed causes of back pain in young people, frequently dismissed as muscle strain for months or years before the correct diagnosis is made.

Spondylolysis is not dangerous in most cases but it significantly affects management. A young athlete with an undiagnosed pars stress fracture who continues high-loading activity risks progressing to a complete fracture and potentially spondylolisthesis (vertebral slippage). Early correct diagnosis changes the outcome significantly.

Who gets it?

Fast bowlers (cricket)

Highest reported incidence of any sport — 30–55% in elite fast bowlers. The side-on delivery combines hyperextension with rotation at speed.

Gymnasts

Repeated walkovers, bridges, and landing positions load the pars relentlessly. One of the most common causes of back pain in young gymnasts.

Rowers

Repeated flexion and extension under load. The catch position is particularly demanding on the pars interarticularis.

Footballers and dancers

Kicking actions and hyperextension positions (arabesque in ballet) create rotational and extension stress at the pars.

General adolescents

Adolescent growth spurts create a period of relative vulnerability even without sport. New back pain in an adolescent should always be investigated.

How to recognise it

Lower back pain in a young, active person — particularly in high-risk sports
Pain significantly worse with extension — leaning back is the most useful clinical sign
One-leg extension test — standing on one leg and leaning back reproduces pain on the affected side
Not improving with rest as expected — typical muscle strains settle; pars injuries often plateau
No leg pain or neurological symptoms in most cases
Standard X-rays may be normal — MRI or CT is required for definitive diagnosis

Why it gets missed

Standard X-rays miss spondylolysis in up to 30% of cases. Symptoms are non-specific — the pain feels like a muscle strain. The key clues are the athlete demographic, the extension aggravation, and the failure to improve as expected. Any young athlete with persistent back pain that worsens with extension deserves imaging beyond plain X-ray.

What helps?

Activity modification and rest from loading

A period of relative rest from the aggravating activity — particularly extension-loaded sport — is essential for healing. The duration depends on the severity of the fracture and imaging findings. Most acute pars injuries require 3–6 months of modified activity.

Brace support

A lumbar brace (Boston overlap brace) is used in some cases, particularly for acute bilateral fractures, to reduce extension loading and promote healing.

Rehabilitation

Core stability, hip flexor flexibility, and progressive return to sport under clinical guidance. Returning to full loading before the pars has healed risks progression to spondylolisthesis.

Surgery

Rarely required for spondylolysis alone unless spondylolisthesis develops. Pars repair surgery exists for bilateral defects in young athletes who have failed conservative management.

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Download the Spondylolysis Fact SheetPDF — printable summary to share with your GP or practitioner