Supplement Table 1.

The 8-week balance-training program: sets of 6 balance exercises performed as circular training ×3 session per week.

Weeks 1-2: Work/Rest: 30/30 s, Sets: 2, Rest Between Sets: 2 min

Standing on one leg and moving the free leg front-back-right-left as far as possible without touching the ground. Standing on one leg, with the other foot positioned inside the knee of the support leg. Raise the toe and maintain balance in this position (flamingo stance). Balancing with both feet on a wobble board. Hands on the waist. High knee skipping on bosu ball. Lateral jump with one leg over hurdle and maintaining balance on landing. Right leg - left leg alternately. One leg bouncing in star-shaped gymnastics hoops, always passing through the central hoop. Emphasis on maintaining balance on landing.

Weeks 3-4: Work/Rest: 45/45 s, Sets: 2, Rest Between Sets: 2 min

Standing on one leg and moving the free leg front-back-right-left as far as possible without touching the ground (eyes closed). Standing on one leg, with the other foot positioned inside the knee of the support leg. Raise the toe and maintain balance in this position (flamingo stance). Balancing with both feet on a wobble board. Hands on the waist. High knee skipping on bosu ball. Lateral jump with one leg over hurdle and maintaining balance on landing. Right leg - left leg alternately. One leg bouncing in star-shaped gymnastics hoops, always passing through the central hoop. Emphasis on maintaining balance on landing.

Weeks 5-6: Work/Rest: 45/45 s, Sets: 2, Rest Between Sets: 2 min

Standing on one leg and moving the free leg front-back-right-left as far as possible without touching the ground (eyes closed). Standing on one leg, on bosu ball. Use the free leg to simulate the movement of the instep pass and straight shot alternately. Balancing with one leg on a wobble board. Hands on the waist. Starting from the ground. Jump onto a bosu ball with both legs – stabilization – vertical jump and land on one leg – stabilization. Alternate landing leg between repetitions. Single leg vertical jumps inside and outside of an agility ladder. Alternate legs between repetitions. Jumps with one and both legs to execute a predefined route with hurdles and hoops. Emphasis on stabilization after landing.

Weeks 7-8: Work/Rest: 45/45 s, Sets: 2, Rest Between Sets: 2 min

Standing on one leg on a bosu ball. Use the free leg to simulate the movement of the instep pass and straight shot alternately. After each soccer move catch a throwing ball with the opposite hand and throw it back. Balancing with one leg on a wobble board (eyes closed). Free hands. Starting from the ground. Jump onto a bosu ball on one leg – stabilization – vertical jump and land on the other leg – stabilization. Alternate legs between repetitions. Bounces on one leg on a mini-trampoline. Stabilize after three bounces and simulate a soccer pass or shot with the free leg. Jumps with one and both legs over hurdles to execute a predefined route. Landing after each jump on stable or unstable surfaces alternately. Standing on one leg and simulate soccer pass and shot with free leg (eyes closed).