Archery and strength in sedentary men: Zolkafi 2020

Thirty-four sedentary young men, randomly split into two groups of 17, were followed for 24 weeks: the first group shot three times a week for 12 weeks and then stopped for another 12, while the second kept to its usual routine. Isometric strength of six muscle groups, measured with a hand-held dynamometer, and grip strength were tested at the start, at 12 weeks and at 24 weeks.

After the archery period elbow flexor strength had risen from 33.60 to 49.06 lbf (+46%), elbow extensors from 29.91 to 41.18, shoulder abductors from 27.90 to 36.60 and knee flexors from 28.91 to 40.31; in the control group the values barely moved. For these four muscle groups and for left grip the group by time interaction was significant, while for knee extensors, hip abductors and right grip it was not. After 12 weeks without shooting strength had fallen in almost every muscle but stayed above the starting values: the elbow flexors, for example, were at 41.71 lbf.

The participants, aged 18 to 30, came from a preliminary survey of 208 people and did less than 150 minutes a week of moderate or vigorous activity; mean BMI was 29.49 in the archery group and 30.75 in the controls. The programme used a barebow, carbon arrows and a target boss at 10 metres, with a three-finger hook (index, middle and ring finger), a cheek anchor, a draw weight of 35 to 40 pounds and about 5 seconds of aiming; each session had 7 sets of 6 arrows, 1,512 arrows in all, under a qualified coach. During the detraining phase participants were asked to avoid any physical activity.

Elbow, shoulder, knee and hip were tested with a Commander dynamometer in a supported position, taking the best of three attempts and averaging right and left; grip was tested with a Jamar dynamometer, seated with the elbow at 90°, as the mean of three trials. The analysis is a 3 by 2 repeated measures ANOVA, and the authors report no dropouts.

This is very probably the same sample as the HRV paper the same authors published in 2019: same ethics approval number, same inclusion criteria, identical body composition values, although weight, BMI and equipment (a wooden bow and fibre arrows there) are not described in the same way.

The archery group started weaker than the controls on grip (73.80 against 82.01 on the right, 66.29 against 77.85 on the left), and part of the gain may come from that. People who have just trained for three months also have more reason to push in the test than people who did nothing, and the paper does not say whether the testers were blinded to group. Units are unclear: the methods say grip was recorded in kilograms, the table gives pounds-force, and mean values between 66 and 91 only make sense in pounds.

The discussion mentions a 24% loss in the hip flexors, which were not measured, and for the knee extensors strength after detraining (48.31) is higher than at the end of the archery period (46.00). The knee flexor gain is explained by body sway while aiming, which was not measured. It is a conference paper with a small, all-male, overweight sample.

The study suggests that for sedentary, untrained people, shooting a 35 to 40 pound bow, 42 arrows a session three times a week, is enough of a stimulus to increase arm strength, especially in the elbow flexors, which work to hold the string. That is a plausible result for people starting from nothing, but it says nothing about trained archers, for whom the same load is their normal routine.

For archers who shoot regularly the most interesting result is the one on stopping: after a 12-week break some of the strength gained had already gone, though not all of it. The explanations of what the leg muscles were doing are the authors' hypotheses.