Plyometric training for archers: Dhawale 2018 study

Six weeks of upper-body plyometrics improved strength, endurance and the score on a shooting test in 60 Indian archers aged 18 to 30, compared with a control group that did not move on any measure.

The archers were split 30 to a group: 14 men and 16 women in the training group, 17 men and 13 women in the controls. In the training group the measure called accuracy goes from 4.93 to 8.13, the closed kinetic chain upper extremity stability test from 9.1 to 19.53, and the one-repetition maximum from 6.03 to 8.83 on the right and from 6.03 to 8.83 on the left, all at p = 0.0001. In the control group every value is identical before and after: 4.5 for accuracy, 7.63 on the stability test, 5.83 on both maxima. The between-group comparison after the intervention gives p = 0.0001 on all four measures, while before it the two groups already differed on accuracy and stability (p = 0.0300).

The paper does not say what units either accuracy or the one-repetition maximum are in, and it does not describe the shooting test: it calls it only a test on the score board. Among their own limitations the authors put first the need for a more reliable way of measuring accuracy.

A controlled trial on 60 archers recruited by what the authors call a simple random method, at the physiotherapy department of Tilak Maharashtra Vidyapeeth in Pune, with ethics committee approval and written consent. The training group did plyometrics for the shoulder and upper back muscles; the control group received ergonomic advice and conventional treatment, which the paper does not describe.

Three sessions a week for six weeks: ten minutes of warm-up, 30 to 40 minutes of work, ten minutes of cool-down. Ten exercises are listed: catching and throwing a weighted ball against a wall or with a partner, first with both arms then with one; stretch-shortening drills with elastic tubing; swinging a weighted object; bouncing a ball on the floor or against a wall for the wrist flexors; pushing off from a wall or a worktop while standing; drop push-ups from a low platform; clap push-ups; two-handed side throws and catches with trunk rotation; overhead throws and catches from hand to hand; bouncing a weighted ball while lying prone, for the shoulder internal rotators.

Measurements were taken before and after the six weeks. The closed kinetic chain stability test was chosen, the authors write, because it is the only upper-limb test with good test-retest reliability. The one-repetition maximum was measured on both sides. Accuracy was collected on the score board, with no mention of distance, number of arrows or target face. The analysis, run in Excel and InStat, uses a paired t test within groups and an unpaired one between groups, with the threshold at 5%.

The first thing that does not add up is inside the paper itself: the abstract says 60 archers split into two groups and then 15 subjects per group, while the demographic table counts 30 people in each. The table figures correspond to 30 per group, and this record follows them.

The control group data are hard to believe. All four measures stay identical before and after, down to the second or third decimal, which does not happen with any repeated measure on thirty people six weeks apart. On top of that, on the stability test the control group has the same starting and finishing values and a p of 0.0042, which identical data cannot produce. The two groups also differed in age (21.1 years against 23.4, p = 0.0069) and started out different on two of the four measures.

None of the measures can be interpreted. Accuracy runs from about 5 to about 8 with no units and no description of the test, so there is no knowing whether these are arrows inside a ring, points, centimetres or something else; a one-repetition maximum of 6 has no units either, and if these were kilograms it would not fit adult archers. The competitive level of the archers is not given, the bow and draw weight do not appear, nothing is said about who took the measurements or whether they knew each archer's group, and the control group's treatment is not described. The authors themselves list the participants' level and the need for a more reliable way of measuring accuracy among their limitations.

The journal displays an SJIF index and an Index Copernicus value on its front page, neither of which is a measure of editorial quality, and the registry record does not state whether the paper went through peer review.

For someone who shoots this paper is little more than a title. That six weeks of plyometric work for the shoulders and upper back raise strength measured as a one-repetition maximum, and endurance in a weight-bearing position on the arms, is plausible and in line with what is known about strength training; that they raise the score cannot be checked here, because the measure called accuracy is never described and the group that did not train does not change by a thousandth on any result.

The one usable part is the list of exercises, which is precise enough to repeat: weighted ball throws and catches, drop and clap push-ups, elastic tubing work, prone bouncing for the internal rotators. These are common exercises, not specific to archery, and the paper does not say at what load or for how many repetitions.

In the registry this source counts as a weak signal on the line about explosive strength in archers, not as evidence that plyometrics raise the score. Anyone training with exercises of this kind is doing so for reasons that come from elsewhere.