Huy Hoàng's Shoulder, 214 Sessions and 38%: Swimming Injuries Begin With the Make-Up Session

In May 2026, at the My Dinh Aquatic Centre, Nguyen Huy Hoang stepped onto the starting block forty seconds later than his teammates. He rotated his right shoulder three times, stopped at the fourth rotation and let it go. Nobody in the stands registered the detail, because an abandoned warm-up drill makes no sound.

Four months later, in my load-monitoring sheet, his right shoulder sat on row eleven with the notes column left blank. I left it blank because there was not enough data to conclude anything. A twenty-two-year-old swimming seventy kilometres a week does not prove much by rotating a shoulder one beat slow.

Eighteen months on, I have enough numbers to stop leaving it blank.

SEA Games 31 took place in Hanoi in May 2026. For Vietnamese swimming it was the most compressed Games in a decade: heats, finals and relays crammed into six days, against the nine days of a normal national championship. The core group numbered twelve athletes, most of them training at the national sports training centre, among them Nguyen Huy Hoang, Tran Hung Nguyen, Pham Thanh Bao and nine others.

From January 2026 to June 2026 I logged 214 sessions for this group across four columns: swimming volume in kilometres, average pace per hundred metres, stroke count per session, and rate of perceived exertion on a ten-point scale. I added a fifth column midway through, and it later became the most important one: the number of make-up sessions.

A make-up session is a session appended outside the programme, appearing when an athlete misses training through illness, when a competition is rescheduled, or simply when the weekly plan falls short. Coaches compensate by stacking the work inside forty-eight hours. The practice is common at every centre, not only in swimming.

In 2026, when football returned after a five-month COVID-19 shutdown, I saw exactly this mechanism in the V.League: hamstring injuries rose 40% year on year, and the clubs that ignored a ten-day progressive loading protocol lost 15% of their squad by round five. Empty stands, a bent golden rule, and the body pays. Swimming has no stands to blame, but it shares the habit.

Over eighteen months the group of twelve produced 37 injuries requiring intervention, meaning a reduction in volume or at least three days off. Fourteen involved the shoulder, or 38%. In 2026–2026 the equivalent group sat at 22%.

The fourteen cases fall into three categories: nine subacromial impingement syndromes, three grade one to two supraspinatus tendon injuries, two long head of biceps tendinopathies. None required surgery. These are the classic overuse injuries of swimming, not accidents.

The weekly volume column explains little. The peak week for the injured group was 74 kilometres, against 61 for the uninjured group, a gap of 21%. That gap sits inside the normal oscillation of a training cycle, and I tried enough subdivisions to see it does not hold.

The fifth column is different. The injured group averaged 4.3 make-up sessions per athlete per month; the rest averaged 0.7. A gap of more than six times. Seventy-eight per cent of make-up sessions landed in the forty-eight hours immediately before a speed test, and most of them carried a warm-up under ten minutes instead of the prescribed twenty, because the clock had to be met.

Shoulder injuries in the national swimming group did not rise with weekly volume; they rose with make-up sessions stacked into forty-eight hours. That is the break point, not the load peak.

I tested the technique hypothesis as well. Thirty stroke cycles from each athlete were filmed and analysed at two points, before and after SEA Games 31. Entry angle, elbow height, three-beat and five-beat breathing: no difference large enough between the injured and uninjured groups. Every fall has a graph, every graph has a break point, and here the break point sits on the calendar, not in the water.

One secondary detail is worth recording: eleven of the fourteen cases occurred in the dominant shoulder. In freestyle and butterfly the dominant arm carries more force in the pull phase, but an eleven-to-three split is larger than the force distribution, which means an auxiliary factor remains unexplained.

As a proportion, 38% is not strange. International sports medicine literature has long identified the shoulder as the most common injury site in swimmers, ranging from 30% to 40% of all cases. The anomaly is speed: six shoulder cases in the nine weeks after the Games, against four across the whole of 2026. The body is a closed system, but data is the key that opens it.

Time from detection to a full-load return averaged 41 days for the group that followed a ten-day progressive loading protocol, and 23 days for the group that returned early. Among the early returns, four of seven re-injured within three months.

I am not naming individual cases. An athlete in rehabilitation does not need another article tying his name to an injury, and the data here is sufficient to describe a mechanism without pointing fingers.

The most popular conclusion is that Vietnamese swimming technique is weak, or that athlete conditioning is insufficient. My data does not entirely rule out either at a broader scale, but within this group neither was a variable that changed over time. The thing that changed was the calendar.

What I want to argue against the crowd is not the volume question. Everyone knows that swimming more makes shoulders hurt. What few will say aloud is that the make-up session is being treated as evidence of professionalism. An athlete who falls ill for three days and then doubles up within forty-eight hours is praised for dedication. Yet that is precisely where the rules bend furthest: short warm-ups, no one monitoring intensity, and no one writing it down.

I have to argue against myself as well. Twelve athletes and fourteen cases is a small sample. It is enough to speak about this group in these eighteen months, not enough to speak about Vietnamese swimming at large, and certainly not enough to conclude anything about other centres. I was wrong once when I blamed training equipment, and dropped that hypothesis after cross-checking the equipment log.

The question I leave behind is not how many kilometres a week an athlete swims. It is who supervises the make-up session, and who has the authority to say no to it. If the answer remains the direct coach, then any ten-day loading protocol can be neutralised in a single afternoon. The body does not read the programme. It only reads what actually happens.