Fatigue and compound shooting: Lankford 2016

Fifteen experienced compound archers shot four arrows at 20 yards when rested and four immediately after exercise, with two different bows, one single-cam and one double-cam, in a randomly assigned order. Aim time did not change: with the double-cam bow 3.49 ± 1.41 seconds rested and 3.72 ± 1.41 fatigued (p = 0.15), with the single-cam bow 3.62 ± 1.14 and 3.59 ± 1.33 (p = 0.67). The distance between the first fatigued arrow and the centre of the best three rested arrows was almost identical with the two bows: 59.07 ± 49.83 mm with the double cam and 59.27 ± 52.69 mm with the single cam (p = 0.96). Heart rate, recorded continuously, has no appreciable relation to that distance: r = -0.024 with the single cam and r = 0.24 with the double cam.

One figure runs the other way. With the double-cam bow the circle enclosing the best three arrows was smaller when fatigued (56.43 ± 31.09 mm) than when rested (80.36 ± 32.38 mm): groups, in other words, were tighter after the run. The authors call this difference significant while reporting p = 0.16, and add that it does not apply to the first arrow, which they regard as the critical one. Their stated conclusion is that an elevated heart rate impairs neither aim time nor the first shot.

The text is a one-page abstract presented at the American College of Sports Medicine meeting, not a full paper: the protocol is there, the detail on the participants almost absent. The fifteen archers are described only as experienced, with no age, sex, years of practice, draw weight or competitive level. Each used both bows, single-cam and double-cam, in a cross-over design with the order randomly assigned, and shot 15 familiarisation arrows at 20 yards before testing.

When rested they shot four arrows at 20 yards, with the instruction to shoot as quickly as possible without compromising accuracy. The exercise was five minutes walking on a treadmill at 10% grade and 2.5 miles per hour, thirty seconds of rest and a 300-yard run at 7 miles per hour on a 1% grade; immediately afterwards, four more arrows under the same instruction. In each set the worst arrow was dropped and the centre of the circle enclosing the remaining three was calculated. The comparison the authors call precision sets the first fatigued arrow against that centre; the one they call accuracy compares the two circles, rested and fatigued. Heart rate was recorded throughout both conditions and aim time measured arrow by arrow, in seconds. The relation between heart rate and the first arrow was computed as a Pearson correlation.

The biggest limitation is what the document is: one page of conference proceedings, with no tables, no confidence intervals and no description of the sample. For fifteen archers there is no age, sex or level, nothing on the bows beyond the cam type, and no statement of how many arrows entered the comparisons beyond the four per condition.

The figures are inconsistent. The text calls a difference with p = 0.16 significant, which it is not by any usual threshold. Heart rate is the centre of the hypothesis, yet its values are never reported: there is no telling how high the pulse was after the run, so there is no telling how hard the exercise was to which the absence of an effect is attributed. The standard deviations of the arrow distance, about 50 mm on a mean of 59, are as large as the mean itself, and with fifteen people there is little power left to see small differences.

The protocol measures the immediate effect of a short run on compound archers at 20 yards, so it says little about the fatigue that builds over a day of competition, about recurve, or about long distances. The instruction to shoot quickly moves the movement away from ordinary shooting, where the timing is the archer's own. And the test concerns the first arrow after exercise: an unchanged aim time says nothing about the rest of the end, when the effort is over but the tiredness is not.

For an archer the content comes down to one thing: in these fifteen compound archers, stepping to the line with the heart still racing after five minutes uphill and a short run did not lengthen aim time or displace the first arrow any more than the other bow did. The cam type changed nothing, and heart rate did not predict how far the first arrow fell from the rested group.

The conclusion should be taken for what it is: a conference abstract on fifteen people, with a few minutes of exercise and four arrows per condition. There is nothing here about the tiredness of a 72-arrow qualification round, about recurve, about Olympic distances, or about field archery, where the walk between pegs is over uneven ground with the bow in hand. Even the curious finding of tighter groups when fatigued does not hold up: the difference does not pass the threshold the authors themselves state.

The value of this record is in noting that the question has been asked of archers, and that the available answer is this one, small and preliminary. A single arrow shot out of breath, in fifteen people, did not show the deterioration most would take for granted.