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Health first

Overuse injuries: the basics for parents.

Tonight, log the session with its real duration, and if your athlete mentioned a sore anything, write that down too. That one-minute habit is the load history a clinician will ask for first. Two kinds of injury exist: acute (a rolled ankle) and overuse (the same motion, repeated, without enough recovery). Across all ages, two-thirds of tennis injuries are overuse, and most of that is preventable with gradual builds, real rest, and adults who notice early.

This guide is general information for parents, not medical advice. For pain that lasts more than a few days, changes how your child moves, or worries you, see a physician or a sports medicine professional. Sources are named in the text; the athlete's clinician decides.

Why overuse is the junior tennis injury

It is common even at the top of the junior game, and the modern numbers are consistent. A 2025 systematic review of 37 studies puts junior incidence at 2.1 to 3.5 injuries per 1,000 hours, with roughly half of juniors injured in a season (Amor-Salamanca and colleagues). In the largest adolescent tennis cohort to date, 301 Swedish competitive players aged 13 to 19 followed every week for a year, 43% had at least one episode of back pain and 44 of 269 a first shoulder overuse injury, and each additional week in which training spiked above the player's recent normal raised the rate of both (Johansson and colleagues, 2022). The Tennis Australia and Irish national cohorts show the same shape from the other side: incidence rises with age, and the under-16 year is the spike (Gescheit 2019; O'Connor 2020). The same review found that planned four-week ramp-ups and core plus rotator-cuff work each cut injuries by about a quarter, which is the whole case for gradual builds, real rest, and adults who notice early.

The body map: where juniors get hurt

Start with the honest junior picture: in young players, lower-body injuries are twice as common as arm or spine injuries, and the ankle is the most common site; the classic adult problems, tennis elbow included, are less common in younger players (Bylak and Hutchinson). The all-ages list (shoulder, wrist, elbow) matters more as the serve and hitting volume grow through the teens.

Training load: the acute-to-chronic idea in plain words

Compare this week (acute) with the athlete's recent normal (chronic, the average of the previous few weeks). The ratio is a rough index of how prepared the body was for what it just did. Gabbett's 2016 model, built on adult team sports, put the sweet spot around 0.8 to 1.3 and the danger zone at 1.5 and above; the adolescent tennis cohorts measured it directly and found the risk starts lower: each week above 1.3 times the player's own four-week average raised the rate of shoulder injury by about a quarter and back pain by about a sixth (Johansson 2022), and the 2025 review names spikes of 1.3 or more the strongest external predictor in juniors. Excessive and rapid increases in load, not high load itself, are the likely culprit; a steady base is protective. The honesty note: managing load by the ratio has not been shown to prevent injury (Impellizzeri and colleagues, 2020), so treat it as a smoke detector for sharp ramps, never a diagnosis. In junior tennis the classic spike is camp week, a tournament stacked on a full practice week, or the first week back after a break. The AAP's rule of thumb is to add no more than 10% to 20% to weekly load at a time.

Age-appropriate volume: the numbers adults should know

Warning signs: what to watch before it becomes an injury

The AAP's four stages of overuse pain, in order: pain after play; pain during play that does not yet hurt performance; pain that keeps them off the court; pain at rest. The job is to act at stage one or two. Movement tells on them: a serve that changes shape, a shortened follow-through, favouring one side, limping between points, icing after every session without being asked. The burnout side: the AAP defines it as exhaustion plus a reduced sense of accomplishment, and the everyday tell is that practice stopped being fun. Overtraining shows up as persistent fatigue, impaired sleep, and mood changes, and in girls, missed periods belong on the same list. About 70% of children drop out of organized sports by age 13 (AAP). Playing through pain is a habit, not a virtue: ask the question out loud after practice, and make the honest answer cheap.

Rest and sleep are training

Tendons take time: USTA's sports physician piece explains that tendons lose collagen in the 24 to 36 hours after activity and need roughly 2 to 4 days to rebuild, so back-to-back hard days stack that deficit. Sleep is the cheapest injury-prevention program there is: in one study of high-school athletes, those averaging under 8 hours were 1.7 times more likely to be injured (Milewski 2014). The AASM guidance, which the AAP endorses: 9 to 12 hours for ages 6 to 12, 8 to 10 for 13 to 18. Rest alone is not rehab, either: a tendon wants to be loaded gradually, a month of doing nothing often returns the same pain, and a graded plan from a professional is the fix. Surfaces count as load changes; introduce new courts slowly (Bylak and Hutchinson; USTA).

When to see a doctor, and whom

Where TierBreak fits

TierBreak's part is the record, not the diagnosis. The one-minute session log captures duration by category, and a planned rest day on the Schedule counts as a day won, so the load history a clinician asks for already exists, one night at a time. On top of that sits the training-load notice: arithmetic, not AI, free, and outside every quota and consent gate. It compares the last seven days of tracked training time with the average of the four weeks before them, says nothing until it has three weeks of history, and only a week above 1.3 times that average produces a calm notice, with the caveat that only tracked time counts. The daily wellness check-in puts sleep beside load, the Sunday Weekly Review shows hours by category, and a connected coach reads the same week, so the "is this too much?" conversation happens on the same numbers. The app's own training bands follow the caps on this page.

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