ABSTRACT
Foot core system comprises active subsystem, passive subsystem and neural subsystem, which complement each other and provide different function for foot. Insufficient foot function (weak muscle strength, hypoesthesia of foot) is an important cause of foot injury, and aging, obesity and abnormal foot type are also possible factors of foot injury. At present, special foot strength enhancement methods, minimalist shoes training, and even the means of muscle/brain stimulation, can strengthen the intrinsic muscle strength of foot, improve the stability of the foot, increase the plantar sensory inputs, thereby enhance the core system, raise the foot function performance, and prevent sports injury.
ABSTRACT
@# Objective To establish the optimal epidemical trend prediction model of influenza in Jiangxi Province and provide scientific guidance for influenza prevention and control. Methods Monthly influenza sentinel surveillance data of Jiangxi Province were derived from the “Influenza Surveillance Information System In China” from 2013 to 2017, and the different forecasting methods were used to build model, such as autoregressive(AR),exponential smoothing(ES) and autoregressive integrated moving average(ARIMA), also compared predictions with actual values in 2017. Results R square of the three models were 0.731, 0.751 and 0.815 respectively; the root mean square error(MRSE) were 0.253, 0.243 and 0.212, respectively; mean absolute error(MAE)were 0.189, 0.178 and 0.151, respectively; mean absolute percentage error(MAPE) were 10.092, 9.523 and 8.124 respectively; the average relative error (MRE) were 11.45%, 10.92% and 8.96%, respectively. Conclusions ARIMA was a good model for predicting the percentage of influenza-like illness in outpatient visits in Jiangxi Province.
ABSTRACT
Objective To compare the influence of two fatigue protocols on kinematics of lower extremities as well as time/frequency-domain characteristics of impact force during human landing. Methods A total of 15 trained male athletes (sprint/jumping events) were selected and their kinematics in sagittal/frontal plane and time/frequency-domain characteristics of ground reaction force (GRF) under pre- and post-fatigue conditions with two fatigue protocols (constant speed running, shuttle running + vertical jumping) were collected by the Vicon motion capture system and Kistler 3D force plates. Results (1) Both fatigue protocols showed a significant decrease in the angle of hip and knee joints on the sagittal plane, and an increase in the flexion range of motion (ROM). The running + jumping fatigue protocol showed a significant increase in the flexion ROM of ankle joint, the maximum flexion angular velocity of knee joint (P<0.05), the abduction ROM of hip joint and the maximum abduction angular velocity of hip and knee joints (P<0.05). (2) No significant differences were found in time/frequency-domain characteristics of impact force between pre- and post-tests for both fatigue protocols. The running and running + jumping fatigue protocols showed lower amplitude spectra of the GRF in the frequency domain at 3.51, 8.20 Hz and 1.17, 3.51, 7.03 Hz, respectively (P<0.05). Conclusions Both fatigue protocols can induce a more flexed landing posture of lower extremities under the impact of landing, and the running + jumping fatigue protocol shows a better effect with shorter intervention time, which indicates such fatigue protocol has more advantages from the perspective of experimental methodology. The research findings can provide further references for studying force characteristics after fatigue.
ABSTRACT
Objective To investigate the influence of barefoot running and shod running with different foot-strike patterns on characteristics of plantar pressures. Methods Kistler force plates and Medilogic insole plantar pressure system were used to collect and compare the kinetic data from a total of 12 healthy male volunteers under shod and barefoot conditions with heel-toe run and toe-toe run at the speed of 3 m/s, including the GRF, loading rate, plantar pressure and impulse. Results (1) Shod running with heel-toe strike significantly reduced the maximum loading rate and extended the time to reach the peak of impact force. Under forefoot strike pattern, shod running significantly increased the maximum push-off force than barefoot running. (2) More plantar pressure parameters were influenced by the foot-strike patterns as compared to those under the shod conditions, and there was a significant difference in the peak pressure and the time to reach the peak pressure in the mid-foot and heel region between the two foot-strike patterns. Conclusions The foot-strike pattern shows a more obvious influence on plantar pressure during jogging than the shod conditions. Shod running with heel strike can reduce the impact force, while barefoot running with forefoot strike can cause an excessive concentration of plantar pressure on the forefoot region, which indicates that a suitable pair of sports shoes is needed for both foot-strike patterns to reduce plantar pressure during jogging.
ABSTRACT
Objective To compare the influence of two fatigue protocols on kinematics of lower extremities as well as time/frequency-domain characteristics of impact force during human landing.Methods A total of 15 trained male athletes (sprint/jumping events) were selected and their kinematics in sagittal/frontal plane and time/frequency-domain characteristics of ground reaction force (GRF) under pre-and post-fatigue conditions with two fatigue protocols (constant speed running,shuttle running + vertical jumping) were collected by the Vicon motion capture system and Kistler 3 D force plates.Results (1) Both fatigue protocols showed a significant decrease in the angle of hip and knee joints on the sagittal plane,and an increase in the flexion range of motion (ROM).The running + jumping fatigue protocol showed a significant increase in the flexion ROM of ankle joint,the maximum flexion angular velocity of knee joint (P＜0.05),the abduction ROM of hip joint and the maximum abduction an gular velocity of hip and knee joints (P ＜ 0.05).(2) No significant differences were found in time/frequency-domain characteristics of impact force between pre-and post-tests for both fatigue protocols.The running and running + jumping fatigue protocols showed lower amplitude spectra of the GRF in the frequency domain at 3.51,8.20 Hz and 1.17,3.51,7.03 Hz,respectively (P＜0.05).Conclusions Both fatigue protocols can induce a more flexed landing posture of lower extremities under the impact of landing,and the running + jumping fatigue protocol shows a better effect with shorter intervention time,which indicates such fatigue protocol has more ad vantages from the perspective of experimental methodology.The research findings can provide further references for studying force characteristics after fatigue.
ABSTRACT
Objective To investigate the influence of barefoot running and shod running with different foot-strike patterns on characteristics of plantar pressures and ground reaction force (GRF).Methods Kistler force plates and Medilogic insole plantar pressure system were used to collect the kinetic data from a total of 12 healthy male volunteers under shod and barefoot conditions with heel strike and forefoot strike at the speed of 3 m/s,including the GRF,the peak impact force,the maximum loading rate,the peak plantar pressure and impulse.Results (1) Shod running with heel strike significantly reduced the maximum loading rate and extended the time to reach the peak impact force.Under forefoot strike pattern,shod running significantly increased the maximum push-off force than barefoot running.(2) More plantar pressure parameters were influenced by the foot-strike patterns as compared to those under the shod conditions,and there was a significant difference in the peak pressure and the time to reach the peak pressure in the mid-foot and heel region between two foot-strike patterns.Conclusions The foot-strike pattern shows a more obvious influence on plantar pressure during jogging than the shod conditions.Shod running with heel strike can reduce the impact load,while barefoot running with forefoot strike can cause an excessive concentration of plantar pressure on the forefoot region,indicating that a suitable pair of sports shoes is needed for both foot-strike patterns to reduce the plantar pressure during jogging.
ABSTRACT
Objective To investigate the influence of barefoot running and shod running with different foot-strike patterns on characteristics of plantar pressures and ground reaction force (GRF).Methods Kistler force plates and Medilogic insole plantar pressure system were used to collect the kinetic data from a total of 12 healthy male volunteers under shod and barefoot conditions with heel strike and forefoot strike at the speed of 3 m/s,including the GRF,the peak impact force,the maximum loading rate,the peak plantar pressure and impulse.Results (1) Shod running with heel strike significantly reduced the maximum loading rate and extended the time to reach the peak impact force.Under forefoot strike pattern,shod running significantly increased the maximum push-off force than barefoot running.(2) More plantar pressure parameters were influenced by the foot-strike patterns as compared to those under the shod conditions,and there was a significant difference in the peak pressure and the time to reach the peak pressure in the mid-foot and heel region between two foot-strike patterns.Conclusions The foot-strike pattern shows a more obvious influence on plantar pressure during jogging than the shod conditions.Shod running with heel strike can reduce the impact load,while barefoot running with forefoot strike can cause an excessive concentration of plantar pressure on the forefoot region,indicating that a suitable pair of sports shoes is needed for both foot-strike patterns to reduce the plantar pressure during jogging.
ABSTRACT
Objective To study the effects by wearing high-top and low-top basketball shoes on kinematics, kinetics and sports performance of ankle joint in sagittal plane under different jumping maneuvers. Methods Twelve subjects were required to wear high-top and low-top basketball shoes to perform drop jumps(DJ) and lay-up jumps(LJ), and the parameters such as minimum/maximum joint angle, torque, power, stiffness, jumping height and dorsiflexion angle during their jumping maneuvers were simultaneously collected by the Vicon motion capture system and Kistler force plates. Results (1) The dorsiflexion angle of ankle joint was significantly decreased when wearing high-top basketball shoe (P<0.05). During DJ and LJ, no significant differences were found in jumping height, touch-down ankle angle, minimum/maximum ankle angle, and ankle range of motion (ROM) in the two shod conditions. (2) There were no significant differences in flexion/extension torque and power of ankle joint in the two shod conditions during DJ. However, during LJ, the peak value of plantarflexion torque and power from wearing high-top shoes was significantly smaller than that with low-top shoes (P<0.05). Conclusions Wearing high-top shoes do not restrict the performance of ankle plantarflexion and dorsiflexion under actual jumping situation. However, the kinetics of ankle joint in sagittal plane under different jumping maneuvers can be partly restricted. The selection and design of shoe collar height should be carefully considered to improve the mechanical effect of ankle joint in sagittal plane and optimize sports performance along with considering ankle protection.
ABSTRACT
Objective To explore the influence of footwear and barefoot on movement coordination of the lower extremities and metatarsophalangeal (MP) joints during push off phase in typical lunge footwork of badminton, so as to provide theoretical basis for scientific training of badminton, as well as choice and development of badminton shoes. Methods Male badminton elites were recruited and required to perform the typical push-off footwork in playing badminton under two shod conditions (commercial badminton footwear and a prototype) and the barefoot condition. A Vicon motion capture system and a high-speed video camera were simultaneously employed to collect the kinematics and coordination characteristics of the hip, knee, ankle and MP joints during the push-off stage of the lunge step. Results (1) No substantial difference was found in joint kinematics of the lower extremities during push-off stage for wearing two types of badminton shoes adopted in this study. Compared with barefoot, wearing badminton shoes could increase the angular velocity of ankle and MP joints to some extent and significantly decrease the time of peak angular velocity occurrence in each joint; (2) With respect to characteristics of movement coordination, the hip, knee, ankle and MP joints were accelerating successively in a proximal-to-distal way during push-off under three foot-shoe conditions. Conclusions Footwear can provide the dynamic source during push-off, and contribute to improve the velocity and effects of push off in order to enhance performance. The movement coordination of the lower extremities during push off in the lunge step is more inclined to be a rational combination of sequence and synchronization. Consequently, more attention should be paid to the speed/strength training of the ankle and MP joints.
ABSTRACT
Objective To explore the influence of basketball shoes on impact force and corresponding muscle activation in the lower limb during the active and passive landing. Methods Twelve male ball players wearing two types of shoes (basketball shoes with cushioning insole vs. control shoes) performed the jump drop and passive landing from three different height on the tiltable platform. The dynamometric platform and electromyography (EMG) measurement system were used to collect the impact forces and EMG data from 5 major muscles in the lower limb simultaneously. Results As for the active drop jump, wearing basketball shoes didn’t have any effect on the amplitude/frequency of impact forces and muscle activation in the lower limb. However, during the passive landing, wearing basketball shoes could significantly decrease the amplitude of impact forces, the peak loading rate and the input frequency (P<0.05), and the post-activation of major muscles in the lower limb were also significantly decreased (P<0.05). Conclusions During the active landing, the intervention of footwear shows no significantly influence on characteristics of impact forces and muscle activation. However, when the human body does not under the full control of landing, wearing basketball shoes can change the input frequency, decrease the muscle post-activation, and play a positive role in preventing the sports injuries and enhancing the metabolic efficiency during the landing.
ABSTRACT
Comparative analysis of characteristic of species and esterase-isoenzyme of isolates of Polyporus umbel-latus from different regions were processed. The results indicated that isolates of Jizhaoling ( Z) and Zhushiling (ZJ) have significant differences in characteristic, and enzymatic band types of the two species also have significant differences. The homology at genetics between the two isolates is 0% , and consanguinity between the two i-solates is the farthest.
ABSTRACT
In this paper, we expatiate the advance of Tricholoma matsutake including distributing, environment, pure culture, domesticating cultivation and artificial forcing breeding in the area of Changbai Mountain of China.