Training Intrinsic Foot Muscles

The foot intrinsic muscles are increasingly targeted in foot and ankle rehabilitation. The exercises are often difficult to learn initially. The purpose of the proposed study is to examine the effect training the intrinsic foot muscles on performance in selected physical and functional measures such as balance, plantar pressure during gait, vertical jump, and foot posture. In addition,the investigators will compare one group training with traditional exercise instruction methods and one group using an adjunctive modality (neuromuscular electric stimulation) during the introductory phases of exercise instruction. The investigators are interested in how this modality might affect physical and functional outcome measures and if it affects participants' frustration with learning a new exercise.

Arm 1: The purpose of this arm of the study is to determine if a 4-week trial of foot muscle exercises, instructed with passive, active-assisted, and active techniques, affect functional measures such as balance, plantar pressure during gait, and vertical jump. A frustration index will be employed to assess participant frustration with learning a new exercise. 15 will be enrolled in this arm of the study. Arm 2: The purpose of this arm of the study is to determine if a 4-week trial of foot muscle exercises, instructed with neuromuscular electric stimulation (NMES) and active techniques, affect functional measures such as balance, plantar pressure during gait, and vertical jump. A frustration index will be employed to assess participant frustration with learning a new exercise.15 will be enrolled in this arm of the study. Arm 3: This group will not engage in any training, but will serve as a comparator for the two intervention arms.

Short foot exercise protocol instructed utilizing verbal instruction, passive modeling, active-assisted modeling, and active modeling.

Short foot exercises plus NMES. Short foot exercise protocol instructed utilizing verbal instruction, passive modeling assisted by neuromuscular electric stimulation (NMES), active-assisted modeling assisted by neuromuscular electric stimulation, and active modeling.

No exercise intervention; continue normal physical activity, but do not start any new exercise programs

The change demonstrated in clinical test of single limb reach/balance in the anterior, posterolateral, and posteriomedial directions in cm

Change in arch height from 10% weight bearing to 90% weight bearing relative to truncated foot length (in %)

Participant reported workload estimates of Mental, Physical, and Temporal Demands, Frustration, Effort, and Performance. RAW TLX will be utilized, with each component considered individually; the subscales will not be combined. Subscales are rated 0-21; higher scores indicate greater load or difficulty

Inclusion Criteria: Individuals aged 18-30; Participate in physical activity 3 times/week; No neurologic injury/condition; No prior experience with study exercises; No injury to lower extremity in past 2 months; Inability to selectively extend the great toe while the lesser toes remain quiet (indicating INTRINSIC FOOT MUSCLES dysfunction) Exclusion Criteria: Sedentary; Known neurologic injury or condition; Current LE injury that may affect neuromuscular function; Tarsal coalition; Absolute contradiction to manual therapy or neuromuscular electrical stimulation (NMES); Previous intrinsic foot muscle training protocol