Impact of low back pain experience on future occurrence of shoulder pain in adolescent baseball players: A 1-year prospective cohort study.

Background: Low back pain can affect musculoskeletal problems of the upper limb in adolescent overhead athletes. However, few epidemiological studies have examined this causal relationship. This prospective cohort study aimed to investigate the relationship between baseline low back pain experience and the occurrence of future shoulder and elbow pain among high school baseball players.

Arnold tongue of electrochemical nonlinear oscillators.

We study the Arnold tongue of a nonlinear electrochemical oscillator entrained to an electrical periodic forcing. In our system, the width of the 1:3 entrainment region was broader than that of the 1:2 region. The 1:1 and 1:3 regions became monotonically broad when the conductance of the electrode cell was increased by the electrochemical redox reaction of Fe(CN)(6)(4-) <==> Fe(CN)(6)(3-) + e.