Wearable technology in elite sport

A decade ago, knowing how far an athlete ran in a session meant a stopwatch and a guess. Now a GPS unit between the shoulder blades logs every metre, every acceleration, and every collision, and a band on the wrist tracks heart rate and recovery overnight. The data is real and useful. The mistake programs make is treating the readout as the answer rather than as one input that still has to be read against everything else.

This is what the main classes of wearable actually measure, what each signal is good for, and the limits worth knowing before you build a decision on top of one.

GPS and inertial units: the external load picture

GPS units, the kind from Catapult, STATSports, and Polar Team Pro, sit in a vest and track movement: total distance, high speed running, accelerations, decelerations, and, through built in accelerometers and gyroscopes, collisions and changes of direction. This is external load, the work an athlete imposed on themselves, measured from the outside.

The validity research is encouraging but specific. A review of GPS in team sport found units are reliable for total distance during team sport movements, but that lower sampling rate devices have real limitations measuring high intensity running, short bursts, and sharp changes of direction, exactly the movements that matter most in a contact or invasion sport. The practical takeaway: trust distance, treat the sprint and acceleration metrics as directional, and never compare numbers across two different makes of unit as if they were the same instrument.

Heart rate and HRV: the internal load and recovery picture

Where GPS measures the work done, heart rate measures the cost of doing it: internal load, how hard the body worked to produce the output. Two athletes can cover the same distance at very different physiological cost, and heart rate is how you see that difference.

Heart rate variability, the beat to beat variation read overnight or on waking, has become the headline recovery signal on bands like Whoop. A narrative review of HRV monitoring concludes that RMSSD, a measure tied to parasympathetic activity, is the most practical metric, that near daily measurement beats one off readings, and that morning measures are the most informative. HRV is a genuinely useful window into autonomic recovery and accumulated stress, but it is noisy: a single low morning reading means little, while a trend over a week means a great deal.

How accurate are they, really?

Accuracy depends on the signal. An independent study funded by the Australian Institute of Sport and run by CQUniversity tested six consumer wearables against medical grade ECG and sleep lab equipment, and the best performers measured heart rate and HRV at rest very closely against the reference. The honest caveat is that optical wrist sensors degrade during fast, jerky movement, where wrist motion contaminates the signal, which is why chest straps remain the standard for live training heart rate and why some athletes move the sensor off the wrist for hard sessions.

What the data tells you, and what it does not

Used well, wearable data answers concrete questions. Is an athlete's load climbing faster than their base can absorb? The acute:chronic workload ratio, computed from GPS load, is one way to watch that, and the evidence in elite rugby league is that a steadily built chronic base is protective rather than risky. Is an athlete recovering between sessions, or is the readiness trend drifting down? HRV and sleep data answer that.

What the data does not do is make the call. A number is not a context. A low recovery score on a planned heavy day might be expected and fine; the same score on a taper week is a flag. A spike in load is meaningful only against the athlete's history and the injury note the physio logged on Thursday. The signal becomes a decision only when it is read alongside everything else you know about that athlete.

The real problem: signals in separate boxes

Here is the failure that quietly defeats most programs. The GPS data lives in the Catapult portal. The recovery data lives in the Whoop app. The injury note lives in the physio's system. Each is fine on its own and useless for the decision that matters, because the person making that decision has to open three tools and reconcile them in their head at 7am before a session.

The value of wearable technology is not the devices. It is what happens when their signals land on one athlete record and can finally be read together. That is the job of an athlete management system: pull load from one provider and recovery from another onto the same athlete, beside the availability flag from the medical team, so the readout becomes a decision instead of a tab.

How Strong fits

Strong integrates the wearables you already run. Physical load from Polar Team Pro and recovery from Whoop arrive on one athlete record, server side and encrypted, and sit next to the performance medicine and nutrition data for the same athlete. The Monday morning view is the whole squad's recovery against the weekend's load, flagged against anyone the physios have marked unavailable: three platforms read as one screen, which is the only form in which wearable data actually changes a decision.