Effect of Different Training Methods on Stride Parameters in Speed Maintenance Phase of 100-m Sprint Running.

Cetin, E, Hindistan, IE, Ozkaya, YG. Effect of different training methods on stride parameters in speed maintenance phase of 100-m sprint running. J Strength Cond Res 32(5): 1263-1272, 2018-This study examined the effects of 2 different training methods relevant to sloping surface on stride parameters in speed maintenance phase of 100-m sprint running. Twenty recreationally active students were assigned into one of 3 groups: combined training (Com), horizontal training (H), and control (C) group. Com group performed uphill and downhill training on a sloping surface with an angle of 4°, whereas H group trained on a horizontal surface, 3 days a week for 8 weeks. Speed maintenance and deceleration phases were divided into distances with 10-m intervals, and running time (t), running velocity (RV), step frequency (SF), and step length (SL) were measured at preexercise, and postexercise period. After 8 weeks of training program, t was shortened by 3.97% in Com group, and 2.37% in H group. Running velocity also increased for totally 100 m of running distance by 4.13 and 2.35% in Com, and H groups, respectively. At the speed maintenance phase, although t and maximal RV (RVmax) found to be statistically unaltered during overall phase, t was found to be decreased, and RVmax was preceded by 10 m in distance in both training groups. Step length was increased at 60-70 m, and SF was decreased at 70-80 m in H group. Step length was increased with concomitant decrease in SF at 80-90 m in Com group. Both training groups maintained the RVmax with a great percentage at the speed maintenance phase. In conclusion, although both training methods resulted in an increase in running time and RV, Com training method was more prominently effective method in improving RV, and this improvement was originated from the positive changes in SL during the speed maintaining phase.

Determination of Fatigue Following Maximal Loaded Treadmill Exercise by Using Wavelet Packet Transform Analysis and MLPNN from MMG-EMG Data Combinations.

The muscle fatigue can be expressed as decrease in maximal voluntary force generating capacity of the neuromuscular system as a result of peripheral changes at the level of the muscle, and also failure of the central nervous system to drive the motoneurons adequately. In this study, a muscle fatigue detection method based on frequency spectrum of electromyogram (EMG) and mechanomyogram (MMG) has been presented. The EMG and MMG data were obtained from 31 healthy, recreationally active men at the onset, and following exercise. All participants were performed a maximally exercise session in a motor-driven treadmill by using standard Bruce protocol which is the most widely used test to predict functional capacity. The method used in the present study consists of pre-processing, determination of the energy value based on wavelet packet transform, and classification phases. The results of the study demonstrated that changes in the MMG 176-234 Hz and EMG 254-313 Hz bands are critical to determine for muscle fatigue occurred following maximally exercise session. In conclusion, our study revealed that an algorithm with EMG and MMG combination based on frequency spectrum is more effective for the detection of muscle fatigue than EMG or MMG alone.

Effect of exercise intensity on cerebrospinal fluid interleukin-6 concentration during recovery from exhaustive exercise in rats.

The purpose of this study was to investigate the possible role of moderate and strenuous swimming training on plasma and cerebrospinal fluid (CSF) IL-6 (interleukin-6) levels during recovery from exhaustive exercise in rats. Wistar rats were divided into three groups: sedentary control (C), moderately trained (MT) and strenuously trained (ST). MT rats underwent swimming exercise for one hour/day and 5 days/week for 8 weeks. Animals in the ST group began swimming with 1 h/day and swimming duration was progressively increased by 30 min/wk, reaching 2.5 h/day by week 4 and stayed constant for an additional 4 weeks. After all animals underwent an acute exhaustive swimming exercise, animals were divided into 3 groups, and decapitated immediately, 24 and 48 hours after exhaustion to obtain tissue samples. Muscle citrate synthase activity, plasma and CSF IL-6 levels were determined. The citrate synthase activity was found to be higher in MT and ST groups compared to the C group. Although plasma IL-6 levels were found unaltered among all groups, the CSF IL-6 concentration was found to be increased 24 hours after exhaustive exercise of the ST group. We conclude that exercise training intensity is an important factor determining cerebrospinal IL-6 concentration after exhaustive exercise.

Exercise improves visual deficits tested by visual evoked potentials in streptozotocin-induced diabetic rats.

Visual evoked potentials (VEP) can be used as an objective non-invasive method to study the electrical activity of the visual system. Latency and amplitude measurements of VEP demonstrated that diabetes mellitus has been associated with increases in the latencies whereas the amplitude measurements revealed contradictory results. Although physical exercise has been reported to reduce the complications of diabetes mellitus, the effect of exercise on the visual system remains unknown. We investigated the effects of long-term moderate physical exercise on VEP in streptozotocin (STZ)-diabetic rats. We also measured brain thiobarbituric acid-reactive substances (TBARS) to explore the possible contribution of lipid peroxidation on the visual system. Animals were divided into four groups: control (C), control exercise (CE), diabetic (D) and diabetic exercise (DE) groups. Diabetes was induced by a single intraperitoneal injection of STZ (60 mg/kg). Three days after the confirmation of diabetes, DE and CE groups were trained by running on a motor-driven treadmill with a progressive eight-week programme. The animals began running at 10 m/min, 0 degrees slope, 10 min/day and reached a level of 28 m/min, 6 degrees slope, 60 min/day by week 8. TBARS were elevated and VEP latencies were delayed in diabetic rats, indicating diabetes-induced defects in the optic pathway. These prolonged latencies were restored by exercise training. VEP amplitudes of the DE group were found unaltered with the exception of a decrement in P(2)N(2) which represents an early component of VEP, suggesting that exercise improves visual system defects in diabetic animals at different levels of the optic pathway.