We hypothesize lower VAS ratings and a higher pressure pain threshold (PPT) with the use of shock absorbing insoles compared to no insoles for young football players training on artificial turf.
A total of 55 male young football players from AaB football club participated. Participants were block randomized into two groups (with insoles and without insoles). We used pressure algometry and a visual analogue scale (VAS) as methods of measurement of pain. PPT was measured over 13 locations of the plantar foot, leg and lower back on the non-preferred kicking leg. VAS rating included three situations: (1) during activity, (2) at rest, and (3) comfort intensity. Assessments were made before and after three weeks when using polyurethane gel shock absorbing insoles while training on artificial turf.
We found that the usage of shock absorbing insoles caused a tendency for improvement of comfort intensity by 0.8cm (P=0.053) on a VAS. The shock absorbing insoles caused a significant reduction in pain. VAS ratings decreased by 1cm (P=0.012) for "during activity" and 0.8cm (P=0.027) "at rest" after the intervention within the groups with insoles. The average PPT increased significantly by 58kPa (P=0.046) after the intervention for the group with insoles. Moreover, three specific measurement points had a significant increase in PPT by the use of insoles; erector spinae muscle 126kPa (P<0.001), tibialis anterior muscle 89kPa (P=0.014) and metatarsal bone 5 (head) 68kPa (P=0.049).
In conclusion we found a reduction of pain intensity and sensitivity in young football players when using shock absorbing insoles while training on artificial turf.