Effect of dynamic guidance-tubing short foot gait exercise on muscle activity and navicular movement in people with flexible flatfeet.

BACKGROUND: Navicular drop is a common plantar deformity which makes the plantar medial longitudinal arch (MLA) collapse and leads to other deformities in lower extremities. Active structures are from intrinsic and extrinsic foot muscle activities such as abductor hallucis (AbdH), tibialis anterior (TA), tibialis posterior, flexor hallucis brevis, flexor digitorum brevis during dynamic situations. As AbdH plays a role as a dynamic elevator of MLA, the importance of AbdH has been emphasized and the proper recruitment of both intrinsic and extrinsic muscle is crucial for stabilization of MLA during dynamic weight bearing condition. Because the short foot (SF) exercise is difficult to perform and tends to activate the intrinsic muscles concentrically rather than a natural coordination of concentric-isometric-eccentric activation, we have developed the guidance-tubing SF gait (GFG) exercise. OBJECTIVE: We investigated the effect of GFG exercise on muscle activity, AbdH:TA activity ratio, MLA angle, and foot pressure distribution during walking compared to SF gait (SFG) exercise. METHODS: Thirty-two subjects with flexible flat feet were divided into two groups and performed SFG exercise with (GFG) and without guidance-tubing (SFG) for seven serial days. RESULTS: AbdH muscle activity significantly increased from foot flat to heel rise in the GFG group (p = 0.006). The AbdH:TA activity ratio significantly increased in both the SFG (p = 0.015) group and GFG group (p = 0.006). MLA angles significantly decreased in both the SFG group (p = 0.001) and GFG group (p = 0.000), and the decrement was significantly higher in the GFG group (p = 0.001). The foot pressure distribution did not show any statistically significant change. CONCLUSIONS: The result of this study provides a clinical implication for training MLA supporter muscles in individuals with flat feet. The overactive muscle must be inhibited first, then facilitation and strengthening are followed respectively.

Neuroplastic and motor behavioral changes after intermanual transfer training of non-dominant hand: A prospective fMRI study.

BACKGROUND: Intermanual transfer of learning is an important movement basis for a keyboard and instrument playing movement. However, the issue of where neural plastic mechanism occurs in the brain after intermanual transfer training remains both controversial and unresolved. OBJECTIVE: The aim of present study is to investigate the neuroplastic mechanism associated with the interlimb transfer learning from non-dominant hand to dominant hand. METHODS: Twenty healthy right-handed adults were classified into either the control group (no-training) or the experimental group (training serial button-press motor task, SPMT), 5 days a week for two consecutive weeks. SPMT involved pressing the numbers 1, 2, 3, and 4 in a random sequence, which was presented in the monitor screen. Outcome measures included movement accuracy (MA), movement time (MT), and the fMRI data using a 3T MRI scanner. Repeated measures of analysis of variance (ANOVA) and non-parametric tests were used at p <0.05. RESULTS: Motor performances in the MA and MT were significantly more improved in the experimental group than in the control group (p <0.05). Neuroimaging data revealed a distributed subcortical and cortical motor network including the SMA-thalamus (VL/VL)-basal ganglia-cerebellum loop, suggesting a differential and time-dependent neural network utilized during intermanual transfer learning. CONCLUSION: Pre-training intermanual transfer learning involved a form of declarative (or explicit) motor learning, which was primarily mediated by the cortical motor network, whereas post-training involved a form of procedural knowledge, which activated subcortical and cortical motor network regions, including the SMA-thalamus (VL/VL)-basal ganglia-cerebellum loop.