Taewoong Kim on the shared testing protocol, twice-weekly jump tests and microdosing behind Peterborough United's pathway

Coaches ask Taewoong Kim the same question all the time: where are the young players compared with the first team? Kim is the First Team Sport Scientist at Peterborough United, and in October he answered it on stage at the NSCA conference in Verona, in a talk called Building the Pathway. A few days later he and I sat down and went back through it slide by slide.

Peterborough run their performance data on Axon, so I'd seen parts of this work from the data side. What I hadn't heard was the whole thing laid out in one go, the testing, the reporting, what it changes in a training week, and the parts Kim says plainly he can't measure yet. The full conversation is below, and this is the written version for anyone who'd rather read it.

One protocol from the under-18s to the first team

Kim is straightforward about where the club sits. In his words it's a small budget and big dreams, and the target that comes out of that is a concrete one: three or more academy graduates a season into the first team, each playing more than ten first-team games. He came up that way himself, promoted internally from the academy, and he describes the two staffs as working to one team, one principle.

He opened the talk with four standards: communication, a player-centred approach, context behind the numbers, and every detail mattering, down to the decimals. Communication came first because the sport scientist isn't the only one making decisions, the coaches and the medical staff are in it too.

The principle in practice is a shared protocol. Of the three things Kim asked the room to remember, this was the first: "Shared protocol makes the gap measurable." The under-18s and under-21s test four times a year, from pre-season to either side of Christmas, and the first team is measured against the same benchmarks. The battery covers anthropometrics (growth and maturation markers are a big part of long-term athletic development at that age), strength and power, running, and two run-specific tests on VALD, a hip and a knee isometric push. Those two look at the angles where hamstring and knee soft-tissue injuries happen when players sprint, and the club follows VALD's protocol so it can benchmark against the Premier League data VALD publishes.

Numbers a coach can read

The numbers are only where it starts for Kim. What he's after is the story behind them, and he treats the work as a loop, every day, every week, every month, rather than a one-off report, so today's story becomes tomorrow's baseline. When the data can't tell the story, he goes and talks to the player.

A coach isn't going to get much from a number on its own, so the test results go out four ways. A RAG rating, so nobody needs to know what a good number looks like. Z-scores for a second visual. Relative rankings, which he rates the best of the lot, because what coaches want to know is where a player sits, and the rankings stay inside each age group, under-18s against under-18s, first team against first team. Then percentage change from one test to the next.

On top of that, every player gets a smallest worthwhile change to hit by the next test. Kim's experience is that once players have a target they work hard to get over it, and the next job for him is tracking whether they stay in that loop once they've hit it.

Two jump tests a week, on the days that matter

Peterborough used to run CMJ testing every day. Now it's twice a week, on Match Day +2 and Match Day -2, and I asked Kim whether dropping the daily test had cost them anything. His answer was about timing. Those are the two days that matter, and testing a whole squad takes a fair bit of time, time the staff need in the morning to prep the session, the gym and the warm-up on the pitch. He doesn't feel they've lost anything.

MD+2 is where most of the flags show up. Kim's view is that one day off with a recovery session on their own isn't enough, so the prep and gym sessions that week are adjusted to get more recovery in. MD-2 is the last point to adjust prep before the game.

He doesn't read one number either. Each jump is read across six metrics: concentric impulse, eccentric deceleration RFD, eccentric braking impulse, jump height, RSI modified and contraction time. RSI modified is the popular one for fatigue, and on its own he found it wasn't enough. His example is a player whose jump height holds at baseline, which looks fine, but whose contraction time has risen, a compensatory signal that gets him flagged and his prep session changed. Each test is set against the player's 7-day trend and a 21-day running average to decide who's flagged.

The academy already runs at first-team intensity

Kim is tracking high-speed distance per minute on match days across both groups. Over the first six match days the first team averaged 8.82 and the academy, under-18s and under-21s combined, 8.43. He's careful with it: six match days isn't a season, he isn't arguing with the published research, and he expects the picture could change once he has a full season. But some academy players, and some academy games, are already over the first-team average.

That's behind the third of his takeaways. "This is a maturation gap, not a performance gap. For the academy players, match output is already adult level, however the body isn't." Even at 21 physical maturation isn't finished, because tendon and bone density keep developing into the mid-twenties, so the club can't ease off the programme for a young player who's already running like a first-teamer. That's what the run-specific testing is there for, and the microdosing.

His second takeaway sits alongside it: output alone doesn't clear a player or rebuild a gap, so movement strategy, training exposure and match context each get checked on their own.

Same tool, opposite direction

The under-21s play on a Tuesday and the under-18s on a Saturday, so the under-21s microdose on the Friday and the under-18s on the Thursday. Each session runs prep pattern, main exercise, accessory, dynamic effort, then positional work, and it's built from the player's testing numbers and injury history. It's done as prep before they go out on the pitch, and it sits alongside a main lifting session, never in place of one, because for Kim the gym is where the strength and power come from.

The direction is what changes between the squads. In the academy, baseline high-speed exposure is low, so the sessions are targeted, gated sprints to close the gap before a player's first minutes. The first team already carry a high weekly volume with little room to add to it, so the job there is protecting top-speed quality inside that volume. Kim's summary of it was "same tool, opposite direction, same principle". What goes into each week's sessions comes from that week's training and match data, and the jump test can decide whether a player microdoses at all.

Where the data lives

Peterborough's VALD and Catapult data comes in raw, through one login each, into Axon, which is connected to Claude, and Kim writes his own Python scripts to turn it into the reports the club uses, published so the coaches can open them and read them easily. He did the same job in Power BI before. His verdict is that it was slower and less visual, and data visualisation matters more to him than anything else. One of the reports sets each player's training output as a percentage of his own match-day numbers, calculated automatically, so the staff can see how a session's intensity compares with a game.

I asked him about the learning curve with Claude. He started in Excel, moved to Power BI, and found that what he'd learned there carried straight across to Python and HTML reports.

What they can't measure yet

Kim was straight about the gaps. Everything in the talk is physical. The research is clear that psychosocial readiness matters, and the club doesn't measure it yet. There's no psychologist at Peterborough, and he thinks the wellness forms do part of the job but need more detail than they give.

The readiness gate and the microdosing don't have validated outcomes yet either. His plan for this season, his first with the first team, is to count the non-contact soft-tissue injuries at the end of it, compare each player's testing data from the start of the season with the end, and see whether they've improved. Then he'll keep going for the season after, and the one after that.

How the two staffs work together

The last thing I asked about was communication, since Kim had put it first in his list of standards. Day to day, the academy trains at the same time as the first team, so if the first team start at eleven, so does the academy, and the first team regularly call academy players up. Because both groups run on the same protocol, the staff know before anyone walks out who might be going up that day, and whether he's physically ready to train with the first team.

Jon Foote is the founder and CEO of Axon Perform. He has spent twenty years in data and analytics, the last six of them in high-performance sport, working with the All Blacks since 2020 and with the Springboks, the British & Irish Lions and clubs across rugby, football and cricket since. Axon won Innovation in Sport at the 2026 Otago Sports Awards. Start a trial.