Locomotor pattern gradually degrades with removal of proprioceptive feedback. A) Chronic EMG recordings were made during treadmill locomotion and swimming in wild-type and Egr3 mutants that lack functional muscle spindle feedback. B) Bar diagram illustrating the activity of flexor (red) and extensor (blue) muscles during treadmill walking and swimming in wild-type (n = 16 for walking and n = 14 for swimming) and Egr3 mutant (n = 15 for walking and swimming) mice. Each horizontal bar is the average EMG activity in a normalized locomotor cycle (between successive swing or iliopsoas burst onsets for walking and swimming, respectively). GM, gluteus maximum; IP, iliopsoas; St, semitendinosus; TA, tibialis anterior; VL, vastus lateralis. Reproduced and modified from (10).