Where should our legs be when we do pull-ups or chin-ups

I often see people doing pull-ups / chin-ups with knees bent such that their legs are "hanging" behind. Shouldn't the legs be straight down, perpendicular to the ground? Where should our legs be w

PROGEAR 1300 Adjustable And Foldable 12 Position Heavy-Duty Weight Bench With An Extended 800lb Weight Capacity And Leg Hold Down

weights - Can weighted pull-up and dips lead to lower back problems? - Physical Fitness Stack Exchange

PROGEAR 1300 Adjustable And Foldable 12 Position Heavy-Duty Weight Bench With An Extended 800lb Weight Capacity And Leg Hold Down

PROGEAR 1300 Adjustable And Foldable 12 Position Heavy-Duty Weight Bench With An Extended 800lb Weight Capacity And Leg Hold Down

PROGEAR 1300 Adjustable And Foldable 12 Position Heavy-Duty Weight Bench With An Extended 800lb Weight Capacity And Leg Hold Down

Where should our legs be when we do pull-ups or chin-ups? - Physical Fitness Stack Exchange

Chin-ups on a bar versus straps - Physical Fitness Stack Exchange

PROGEAR 1300 Adjustable And Foldable 12 Position Heavy-Duty Weight Bench With An Extended 800lb Weight Capacity And Leg Hold Down

PROGEAR 1300 Adjustable And Foldable 12 Position Heavy-Duty Weight Bench With An Extended 800lb Weight Capacity And Leg Hold Down

PROGEAR 1300 Adjustable And Foldable 12 Position Heavy-Duty Weight Bench With An Extended 800lb Weight Capacity And Leg Hold Down