The Effect of Bicycle Saddle Widths on Saddle Pressure in Female Cyclists.

Choosing an unsuitable bicycle saddle increases the saddle pressure and discomfort during cycling. Women contract sports injuries more easily than men during cycling owing to their anatomy. To investigate the effect of saddle widths on the saddle pressure in female cyclists. Ten healthy women with an average age of 20.7 ± 1.3 years, height of 162 ± and 5.9 cm, weight of 56.1 ± 7.5 kg, and a sciatic bone width of 15.5 ± 1.4 cm were recruited for this study. The distributions of saddle pressure for four different saddle widths (i.e., narrow, moderate, wide, and self-chosen) were recorded using a saddle pressure mat. Participants were instructed to pedal steadily with a frequency of 90 RPM and a load of 150 watts. Thirty seconds of riding data was randomly retrieved for analysis. The trials were conducted with a counter-balanced design to minimize random errors. One-way repeated measures ANOVA was used to compare the saddle pressure of different saddle widths, and the significance level was set at α = 0.05. When wide saddles were used, the maximum and average pressure on the right surface of the posterior ischium were lower than those with narrow (p = 0.001, p = 0.012) and moderate (p = 0.016, p = 0.019) saddles. The area of pressure on the pubic bone was smaller when using a wide saddle than when using narrow (p = 0.005) and moderate (p = 0.018) saddles, and the area of pressure on the right posterior sciatic bone was larger under the wide saddle than under the narrow (p = 0.017) and moderate (p = 0.036) saddles. The average force was greater with the moderate saddle than with the wide (p = 0.008) and self-chosen (p = 0.025) saddles. Using a saddle with a width that is longer than the width of the cyclist's ischium by 1 cm can effectively improve the distribution of saddle pressure during riding, while providing better comfort.

Influences of Lateral Jump Smash Actions in Different Situations on the Lower Extremity Load of Badminton Players.

Badminton atypical actions and hitting movements often occur during the game; therefore, many special footwork methods have been developed to facilitate the rapid movements required to hit the shuttlecock, including quick turning and jumping and quick directional change movements. Studies have shown that the majority of badminton sport injuries occur in the lower extremity joints of athletes. The purpose of this study was to investigate the influences of hitting motion and unanticipated hitting direction on landing mechanics after backhand lateral jump smashing and landing to analyze joint stiffness and torque changes in three lower extremity joints. Recruited sixteen badminton athletes.The capture frequency of the Vicon Motion System (300Hz), Kistler force platform (1500Hz) and Vicon Nexus Version 1.8.5 software were used simultaneously to capture the kinematic and kinetic parameter of backhand side lateral jump smash footwork. The swing actions were divided into two situations, shadow (footwork and racket swinging practice without targets) and hitting (footwork and stroke shuttlecock) actions, whereas the directions were divided into directional and non-directional. Two-way repeated measures ANOVA with the LSD correction was used to compare the differences among the four conditions. The significance level was set to a = 0.05. Results shown that, at the peak of torque, the ankle plantar flexion of the non-directional shadow (p < 0.05) were greater than that of directional shadow (p < 0.05); meantime, ankle torque change of non-directional shadow (p < 0.05) and directional hitting (p < 0.05) was lower than that of non-directional hitting, but the non-directional hitting was larger compared to non-directional shadow (p < 0.05) at the maximum vertical GRF. The hip extension at peak of torque of directional hitting were larger than that of non-directional shadow (p < 0.05). The shadow actions hip flexion angle was larger than that of directional hitting at initial contact, but the non-directional hitting hip abduction was has the significant difference among all the conditioning. The hip flexion angle of non-directional shadow was larger than that of directional hitting (p < 0.05), the hip abduction angle of the non-directional hitting was greater than that of non-directional shadow (p < 0.05) at the peak VGRF. Elite badminton players execute different training movements; the joint stiffness was in the same state. In the hitting actions has greater ankle and hip joint torque than shadow actions. The badminton player was change joint range of motion to adjust lower limbs stiffness.

Effect of Load Carriage Lifestyle on Kinematics and Kinetics of Gait.

Backpacks are commonly worn by many people for multiple purposes. This study investigated the effects of habitual wearing of backpacks on lower limb kinematics and kinetics. Fourteen participants were recruited for analysis. All participants performed four randomly assigned scenarios, including running and walking at speeds of 3.5 and 1.5 m/s, respectively, with and without load carriage. The motion analysis system and force plate were used to investigate the lower limb kinematics and kinetics. A paired sample t-test was performed for statistical measurement with a significance level of α = .05. The results indicated that active force, breaking force, impact peak, loading rate, active peak, maximum braking, hip flexion, and hip range of motion were substantially higher under load carriage conditions than under walking condition, however, time to peak was lower. Conversely, during load carriage running, active force, braking impulse, time to peak, ankle plantarflexion, and ankle range of motion were all higher than those during running. Carrying a backpack weighing 10% of the body weight induced different foot strike patterns at both speeds; during load carriage walking, the hip tended to flex more; whereas, during load carriage running, the ankle tended to flex more. In conclusion, human body seems to adopt different gait strategies during load carriage walking and running. That is, the hip strategy is used during walking, while the ankle strategy is used during running.

The acute effects of whole body vibration stimulus warm-up on skill-related physical capabilities in volleyball players.

Whole body vibration (WBV) has been suggested to improve athletes' neuromuscular strength and power. This study investigated the effect of single WBV stimulation on volleyball-specific performance. The participants were 20 elite male volleyball players who performed a 1-min warm-up exercise on a vibration platform at a frequency of 30 Hz and peak-to-peak displacement of 2 mm. After the warm-up exercise, the participants performed a blocking agility test (BAT), 10-m sprinting test, agility T-test, and counter movement jump test. We compared the participants' performance at four time points (Pretest, Post 0, Post 1, and Post 2). The results revealed that the participants' BAT performance and maximum rate of force development improved significantly 1 min after the vibration stimulation (p < 0.01). The WBV (frequency of 30-Hz, peak-to-peak displacement of 2 mm) intervention significantly improved the volleyball-specific defensive performance and speed strength of the participants. Accordingly, by undergoing WBV as a form of warm-up exercise, the technique and physical fitness of volleyball players can be improved.