In this study, we tested the hypothesis that, during the regular in-seasonal basketball training, an additional 7-week plyometric training program improves lower extremity strength, balance, agility, and jump performance in adolescent female basketball players. Eighteen female basketball players less than 17 years of age were randomly assigned into an experimental group (plyometric training) and a control group. Both groups underwent the same basketball training program. Pre- and post-training test periods included quadriceps and hamstring strength, balance, jump performance, and agility measurements. Illinois agility test time (p = 0.000) and quadriceps strength (p = 0.035) increased uniformly in the two groups. Significant group by test period interaction was found for countermovement jump (p = 0.007), and countermovement height reduced significantly in the plyometric training group (p = 0.012), while it remained unchanged in controls. No significant change was found for T agility test, balance, hamstring strength or H:Q ratio. This study shows that the training program used in-season did not improve the measured variables, except for knee extensor strength. It is possible that regular basketball trainings and games combined with high-volume plyometric training did not show positive functional effects because of the fatigue caused by incomplete recovery between sessions.

(1) In the present investigation, we tested the hypothesis that unilateral countermovement jump performance is associated with knee joint stabilization ability during unilateral landing on unstable surface. (2) Twenty-five male sport students were tested for dynamometric knee extension and flexion, and hip abduction isometric strength. Myolectric activity of vastus lateralis and medialis, gluteus medius, and biceps femoris muscles were measured during unilateral countermovement vertical jump performed on a force plate, and during unilateral landing on unstable surface. (3) Vertical jump impulse negatively correlated with biceps femoris activation at landing. Participants with greater hip abduction force performed greater vertical jump impulse, and activated the biceps femoris less when landing on unstable surface. Furthermore, participants with smaller knee flexion/extension torque ratio increased biceps femoris/vastus medialis activation ratio at landing. (4) We conclude that hip abduction strength is an important contributor to unilateral vertical jump performance. Because biceps femoris is considered the synergist of the anterior cruciate ligament, we also propose that hip abductors are primary frontal plane protectors of the knee joint by reducing knee valgus and stress, allowing for smaller biceps femoris co-activation (secondary protection) at landing on unstable surface.

In this study, we tested the hypotheses that, relative to the maximum capacities, ballroom dancing is more intensive for females than males, and that the hold technique (female vs. male) regulates dancing intensity. Ten dance couples were tested in a maximal treadmill test, competition simulation, and stationary dance hold position. Peak heart rate and relative oxygen consumption were measured during the tests, except that oxygen consumption was not measured during competition simulation. Regardless of gender, heart rate increased similarly in the treadmill test and in the competition simulation. In the treadmill test, females achieved an oxygen consumption of 78% of the males (p < 0.05). Compared with males, females achieved 14% higher heart rate (p < 0.05) and similar oxygen consumption during the hold position. Heart rate during competition simulation relative to maximum was greater for females than males. Both heart rate and oxygen consumption measured during the hold, relative to maximum, were greater for females than males. It is concluded that lower class ballroom dancers perform at their vita maxima during competition simulation. Using heart rate as an intensity indicator, ballroom dancing is more intensive for females because of their unique hold technique.

Studies have proven the effectiveness of different weight-bearing exercise interventions for diabetic patients with neuropathy; however, several adverse effects were reported using solid surfaces. Thus, in the present study, we investigated the effects of a novel sand exercise training intervention on biomechanical and functional parameters in seven diabetic patients (age = 62.7 ± 9.7 years) with neuropathy. Patients underwent a 12-week sand exercise training program, using strengthening, stretching, balance, and gait exercises. They were tested for ankle plantar- and dorsiflexion peak torque, active range of motion (ROM), timed up and go (TUG), and bilateral static balance. EMG activity of tibialis anterior (TA), gastrocnemius medialis (GM), and lateralis (GL) muscles were measured during unilateral isometric contraction in plantar- and dorsiflexion. In the intervention period, plantarflexion peak torque improved significantly (p = 0.033), while dorsiflexion torque remained unchanged. Plantar- and dorsiflexion ROM increased (p = 0.032) and (p = 0.021), respectively. EMG activity of GM (p = 0.005) and GL (p = 0.002) measured during dorsiflexion and postural sway in the balance test, as well as time to complete the TUG test, decreased significantly (p = 0.021) and (p = 0.002), respectively. No adverse effect was reported during the intervention period. We concluded that sand exercise training can be a safe and effective method to improve plantarflexion strength, ankle flexibility, and balance, which is reflected in better gait function in patients with diabetic peripheral neuropathy (DPN).