Decrease In Maximal Power Research Articles

The Immediate Effects of Kinesio Taping on the Maximal Power and Muscle Activity of Erector Spinae in Normal Subjects

The purpose of this study was to evaluate the effects of Kinesio taping(KT) on the maximal power and muscle activity of erector spinae. 30 male subjects were allocated in this study and randomly divided into experimental and control groups. All subjects were measured for maximal power of trunk extensors and muscle activities of iliocostalis lumborum, longissimus, and multifidus between pre and post experiment. Maximal power was calculated using a dynamometer(Power Track II, JTECH medical, USA), and muscle activities were calculated using a surface EMG(MP150 BIOPAC System Inc. CA. USA). Maximal power of trunk extensor showed no significant difference between pre and post intervention in both groups(p>0.05). Muscle activity of iliocostalis lumborum, longissimus, and multifidus showed no significant difference between pre and post intervention(p>0.05). Finally, there was no significant difference between Experimental and control group in maximal power and muscle activity of trunk extensor. These study results suggested that KT did not affect increase or decrease in maximal power and muscle activities of trunk extensor.

Reduction of Substrate Noise in Sub Clock Frequency Range

We propose a method of reducing the switching noise in the substrate of an integrated circuit. The main idea is to design the digital circuits to obtain a periodic supply current with the same period as the clock. This property locates the frequency components of the switching noise above the clock frequency. Differential return-to-zero signaling is used to reduce the data-dependency of the current. Circuits are implemented in symmetrical precharged DCVS logic with internally asynchronous D registers. A chip was fabricated in a standard 130-nm CMOS technology holding two versions of a pipelined 16-bit adder. First version employed the proposed method, and second version used conventional static CMOS logic circuits and TSPC registers. The respective device counts are 1190 and 684, and maximal operating frequencies 450 and 375 MHz. Frequency domain measurements were performed at the substrate node with on-chip generated sinusoidal and pseudo-random data at a clock frequency of 300 MHz. The sinusoidal case resulted in the largest frequency components, where an 8.5 dB/Hz decrease in maximal power is measured for the proposed circuitry at a cost of three times larger power consumption.

CHANGES IN MAXIMAL POWER AND FORCE OVER THE COURSE OF A COMPETITIVE COLLEGIATE FOOTBALL GAME

There is a scarcity of research examining changes in maximal power output over the course of a football game and yet such information is important to athlete and coach from both training and game strategy aspects. PURPOSE: To examine the changes in force and power production in the leg extensors over the course of a competitive collegiate football game. METHODS: Subjects were drawn from two groups. Those selected to play (players, N = 10) and ôred-shirtsö (non-players, N = 9) who participated in all activities of the team except did not play on the day of testing. In order to assess changes in lower body strength and power, the subjects were tested for jump performance immediately before the game (Pre), and after each quarter (Q1, Q2, Q3, Post). All testing session took place on the sideline of the field. Prior to the game each subject warmed up by participating in the usual program of exercises completed prior to a football game. Immediately before kickoff the subject was tested on Squat Jump (SJ) and Countermovement Jump (CMJ). Order of testing was alternated between players such that half were tested on CMJ first and half SJ first. The SJ and CMJ tests were all performed on a portable force plate and a position transducer was attached to the subject's waist to measure displacement of the trunk. A computer recorded force and displacement data with power output subsequently calculated. RESULTS: Force and power output was significantly higher in players compared to non-players at several time points with an average peak force of 2229N and 2506N and peak power of 4397W and 5089W for the non-players and players respectively. There were significant changes in force and power output over the course of the game in both groups with an average decrease from PRE to Q2 of 16–24% and 18–20% for the nonplayers and players respectively. CONCLUSION: In non-players there is a considerable decrease in maximal power which remains throughout the game most probably because the initial warm-up effect is transient. For players in the particular game studied, performance decreased most probably due to fatigue and repetitive impact over the first two quarters but as the game intensity diminished they recovered somewhat and by post-game had returned to their pre-game capacity. These results suggest that a) non-players may have to be kept in a higher state of warm-up if they are to be effective if called on to play; and b) decline in maximal performance is significant and important over the course of a collegiate football game and training and game strategy should encompass this.