Archers' shoulder and trapezius: Kim 2020 study

Eight weeks of lower trapezius exercises reduced shoulder pain in 31 high-level Korean archers, but their scores at 70 metres did not change. The archers trained at a university and a high school, with a mean age of almost 19 and about eight and a half years of shooting behind them: 16 followed the programme and 15 acted as controls.

In the training group, pain rated on a 0 to 10 scale fell on average from 4.6 to 2.9, while in the control group it went from 3.2 to 3.7. The WOSI shoulder questionnaire also improved (from 90.1 to 62.0, where a lower value means fewer complaints), as did the Upper Quarter Y Balance Test score on both arms.

At full draw, just before the clicker fell, the ratio of upper to lower trapezius activity dropped from 3.47 to 1.43, the shoulder blade on the drawing side sat slightly lower (from 81.5 to 78.9 degrees) and the draw force line angle went from 10.1 to 7.9 degrees. The other ratios between parts of the trapezius and deltoid, and shoulder abduction, did not change. The score over 15 arrows at 70 metres stayed flat: 132.1 before and after in the training group, 132.9 to 129.8 in the controls, with no difference between the groups.

The archers were allocated to the two groups by stratified randomisation on sex and years of experience. Of the 32 who started, one control dropped out after being selected for the national team. The programme ran three sessions a week for eight weeks, with four exercises lying prone: Y-raise, T-raise, modified prone cobra and external rotation with the shoulder and elbow at 90 degrees. Loads started at 50-60% of one-repetition maximum, in two sets of 15-20, and rose to 60-70% with sets of 8-12, reaching four sets in the last two weeks. The paper does not describe what the control group did over the same period.

Measurements were repeated before and after the programme. Pain was recorded on a 0 to 10 numeric scale; shoulder function with the WOSI questionnaire and the Upper Quarter Y Balance Test, in which the athlete holds a push-up position and reaches with the free hand in three directions. Surface EMG recorded six muscles (upper, middle and lower trapezius; anterior, middle and posterior deltoid) at full draw, normalised to each muscle's maximal voluntary contraction. A frontal camera at 300 frames per second gave scapular elevation, shoulder abduction and the draw force line angle, measured here as the angle between the arrow and the line of the drawing forearm from wrist to elbow. The score was the total of five ends of three arrows shot outdoors at 70 metres on a 122 cm face.

The sample is small, and the groups did not start level on some measures: the training group had more pain (4.6 against 3.2) and a much higher and more scattered upper-to-lower trapezius ratio (3.47 with a standard deviation of 3.50, against 1.57). When a group starts from extreme values, part of any improvement can simply be regression towards the mean. Complaints were mild on average at the start, with WOSI scores of 90.1 and 74.5 on a scale that runs to 2,100, and the paper does not say how many athletes had appreciable pain at baseline.

The paper does not say whether the assessors knew which group each archer was in, and there is no follow-up. The score came from only 15 arrows shot outdoors, with wind, temperature and humidity differing between the two tests, as the authors acknowledge, so a small change would not have shown up anyway. The idea that a lower draw force line is a technical gain is the authors' reading, based on a Korean federation coaching manual, not something measured on the shot. The shoulder blade, shoulder and draw force line angles come from a single frontal camera, so they describe movement in the frontal plane rather than the three-dimensional analysis the abstract mentions; the authors themselves leave the other planes to future studies. The text is in Korean, with the abstract and tables in English.

For an archer whose shoulder is bothering them, the study says something specific: targeted lower trapezius work, three times a week for two months, reduced reported pain more than in the archers who did not do it, and the shoulder blade sat slightly lower at full draw. It does not show that the exercises add points, since the score did not move in eight weeks, and it does not show that they prevent injury, since nobody was followed over time.

For a coach, the useful part is how practical it is: the exercises are done on the floor with light loads, and the programme is described well enough to repeat. Persistent shoulder pain, though, needs to be assessed by a doctor or physiotherapist, and an exercise sheet is no substitute for that.