Low angle of barefoot young man in jeans and puffer jacket sitting on slack line and balancing

slackline slacklining slack line tightrope balance test balancing balance green climbing home exercise exercise active jitter sport physical activity tighten slack low angle sun stretch grass sky fitness tension sunny wobbling barefoot tie wobble tree trees blue sky birch white man bright sitting bush home tight bushes blue shed silver birch silver leaves puffer barn ratchet