Heart rate while shooting arrows: Guru 2020 study

Seven Indian archers of international standard, four compound and three recurve, shot 30 arrows each at 18 metres indoors while wearing a chest-strap heart rate monitor. For each arrow the authors read heart rate at 11 moments, from 5 seconds before release to 5 seconds after, and related it to the arrow's score. Of the 210 arrows the lowest score was an 8, which came up only 7 times; there were 86 nines and 117 tens.

On average the heart slowed from 5 seconds before release until one second after, then rose again up to +5 seconds, although the rise was not significant. On arrows scoring 8, heart rate during aiming was about 8 beats per minute higher than on nines and tens (7.4 to 8.5 beats depending on the second; at -5 seconds the difference from the tens was not significant). Between nines and tens there was no difference: the means were about one beat apart, slightly higher on the tens. The authors put forward the pattern of heart rate during aiming as a tool for monitoring training from the side of the range.

The archers were men from an army sports institute in Pune, mean age 23.9 with 8.5 years of shooting, in their preparation phase; no spectators or coaches were present during the test. After a 15-minute warm-up they shot 10 ends of three arrows, two minutes per end, at 18 metres on the regulation indoor face, using their own equipment. Heart rate was recorded with a Polar V800 monitor, while a video camera at 50 frames per second filmed the archer and the watch together. The release frame was found in slow motion with Kinovea, and from there the authors read the value shown on the watch at each second from -5 to +5. One archer was tested per day, always at the same time.

The comparison between scores uses a one-way ANOVA with arrows as the unit, followed by Tukey's test; the change over time uses a repeated-measures ANOVA, again treating the 210 arrows as 210 subjects.

The main limitation is in how things were counted: 210 arrows from 7 archers are treated as independent observations. Each archer has his own baseline heart rate, and the mere 7 arrows scoring 8 may come from one or two archers with faster hearts; if so, the difference between 8s and 10s would say something about archers, not about shots. The paper does not say whose arrows the 8s were, and the degrees of freedom in the analysis over time (10 and 200) confirm that arrows were counted as subjects.

Heart rate was read from the watch display, which shows a value updated and averaged by the device rather than beat by beat, so changes within a single second are hard to read accurately. Compound and recurve are pooled, and the paper does not say how compound arrows were scored, given that indoors they use the inner 10. There is no comparison group, and all the archers are men from one institute. The discussion states that heart rate fell further on tens than on nines, while the table shows slightly higher values on the tens. The paper carries two DOIs, one from the original publisher and one from the current one.

The slowing of the heart in the last seconds before release has already been described in experienced archers, and this study finds it again with simple tools: a chest-strap heart rate monitor and a video camera. For a coach the interesting point is feasibility, since heart rate during aiming can be followed without a laboratory.

The study does not show that a higher heart rate while aiming leads to worse arrows: the low-scoring arrows are few, nobody knows whose they were, and nothing changed between nines and tens. For archers it is an observation worth knowing about, not a target to chase, because no data here suggest that deliberately lowering one's heart rate raises the score.