"Beach Muscles"

In teams of two, with only one partner working at a time, complete the following for time:
1600 Meter Relay Run (alternating 400 meters)
immediately followed by…
20 rounds (partners alternating full rounds) of…
4 Strict Supinated-Grip Pull-Ups
8 Ring Dips
12 Push-Ups
16 Air Squats
immediately followed by…
1600 Meter Relay Run (alternating 400 meters)