Preseason Conditioning and Overuse Injury Risk: What the Research Shows

Across the Chicago suburbs, August means preseason: soccer and football conditioning is underway, cross country teams are logging their first mileage, and fall sports physicals are filling up waiting rooms. It's also the time of year sports medicine clinics tend to see a rise in overuse injuries — stress reactions, tendinopathies, and growth-plate irritation — as young athletes ramp up activity after a slower summer.

Here's what the sports medicine literature says about why that happens, and what the research supports for reducing risk.

Training Load Ramps Up Faster Than Tissue Can Adapt

Overuse injuries are, by definition, a mismatch between the load placed on a tendon, bone, or growth plate and that tissue's capacity to recover between sessions. A commonly cited guideline — sometimes called the "10% rule" — suggests increasing training volume, intensity, or distance by no more than about 10% per week to give tissue time to adapt.¹ Preseason schedules, which often jump from minimal summer activity to two-a-day practices within a week or two, frequently violate this principle.

Researchers have also studied the acute:chronic workload ratio (ACWR) — comparing an athlete's recent training load to their longer-term average — as a way to flag risk. A 2025 systematic review and meta-analysis found an association between higher ACWR spikes and injury risk, though the authors note real heterogeneity across studies and caution against treating any single ACWR threshold as a hard cutoff.² The broader takeaway holds up: sudden, large jumps in load are a consistent risk factor, even if the exact math is still being refined.

Sport Specialization Adds Independent Risk

A widely cited case-control study out of Loyola University Chicago and Lurie Children's Hospital followed young athletes and found that those who specialized in a single sport had a significantly higher risk of injury, including serious overuse injury, independent of their total training volume or age.³ The American Academy of Pediatrics has echoed this in a policy statement, noting that early single-sport specialization — particularly training more hours per week than an athlete's age in years — is associated with increased injury risk without clear evidence of a performance benefit at young ages.⁴

Recovery Is Part of Training, Not the Absence of It

Guidance from youth sports medicine organizations generally recommends at least one full day off from organized sport per week, along with periodic longer breaks (weeks, not days) from a single sport over the course of a year.⁵ This isn't about doing less — it's about giving bone, tendon, and growth cartilage the recovery window they need to keep up with a rising training load.

A Preseason Movement Check-In Can Help

Because strength imbalances, limited mobility, and movement compensations are easier to address before they cause pain than after, a preseason assessment is a reasonable, low-cost step for athletes ramping back up — particularly those returning from a prior injury or entering a growth spurt.⁵