Pick a vertical or slabby wall that spans between 10 and 30 feet. Traverse back and forth (take breaks in between, this is not an endurance exercise) on easy terrain. Focus on staying on your feet and minimizing upper body involvement. Unless the grip is a two-hand jug, try not to match hands. There are several variations to this exercise:
SILENT FEET
Place each foot precisely with maximum control. Focus on putting your big toe on the best part of each hold.
NO MATCHING
Avoid switching feet on any foothold, regardless of size. Try to use step-throughs instead and focus on shifting your weight from one foot to the other.
STICKY TOES
To emphasize precision do not move your foot (other than pivoting) after it touches a foothold.
FOOT JIBS
Limit yourself to only small footholds and natural features in the wall.
COIN HOLDS
To make footholds more challenging, place coins on their most positive surfaces.
