Muscle strength and activation characteristics of power- trained and non-athlete boys and men

During maturation, muscle strength is enhanced through muscle growth, although neuro-muscular factors are also believed to be involved. In adults, training for power sports has been shown to enhance muscle strength and activation. The purpose of this study was to examine muscle strength and activation in power-trained athletes (POW) compared with non-athletes (CON), in boys and in adults. After familiarization subjects performed ten 5-s explosive maximal voluntary contractions for elbow and knee flexion and extension. The adults were stronger then the boys and the adult POW were stronger then the adult CON, even after correction for muscle size. Normalized rate of torque development was higher in the adults then in the boys and higher in the POW then CON boys. The rate of muscle activation was higher in the adults and POW groups. The results suggest that maturation and power-training have an additive effect on muscle activation.

Canadian Niagara Power Glass Slide - Group of men walking through the hydro tunnel

Four men (unidentified) walking in tunnel wearing hard hats and carrying flashlights.

Canadian Niagara Power Glass Slide - Engineer Drawing of Sections of Discharge Tunnel

Consulting Engineer drawing of Sections of the Discharge Tunnel. Included in the drawing is the "cross section of tunnel with timbering" and "longitudinal section showing Timber in straight tunnel". Dated October 1902.

Canadian Niagara Power Glass Slide - Drawing: Section thru Wheelpit

Drawing of "Section thru Wheelpit" dated September 1925. Shows unit no.1 through unit no.11, power house floor and water surface.

Reduced power output in skeletal muscles devoid of skMLCK: RLC phosphorylation contributes to peak performance

Regulatory light chain (RLC) phosphorylation in fast twitch muscle is catalyzed by skeletal myosin light chain kinase (skMLCK), a reaction known to increase muscle force, work, and power. The purpose of this study was to explore the contribution of RLC phosphorylation on the power of mouse fast muscle during high frequency (100 Hz) concentric contractions. To determine peak power shortening ramps (1.05 to 0.90 Lo) were applied to Wildtype (WT) and skMLCK knockout (skMLCK-/-) EDL muscles at a range of shortening velocities between 0.05-0.65 of maximal shortening velocity (Vmax), before and after a conditioning stimulus (CS). As a result, mean power was increased to 1.28 ± 0.05 and 1.11 ± .05 of pre-CS values, when collapsed for shortening velocity in WT and skMLCK-/-, respectively (n = 10). In addition, fitting each data set to a second order polynomial revealed that WT mice had significantly higher peak power output (27.67 ± 1.12 W/ kg-1) than skMLCK-/- (25.97 ± 1.02 W/ kg-1), (p < .05). No significant differences in optimal velocity for peak power were found between conditions and genotypes (p > .05). Analysis with Urea Glycerol PAGE determined that RLC phosphate content had been elevated in WT muscles from 8 to 63 % while minimal changes were observed in skMLCK-/- muscles: 3 and 8 %, respectively. Therefore, the lack of stimulation induced increase in RLC phosphate content resulted in a ~40 % smaller enhancement of mean power in skMLCK-/-. The increase in power output in WT mice suggests that RLC phosphorylation is a major potentiating component required for achieving peak muscle performance during brief high frequency concentric contractions.

Letter to W.D. Woodruff from E.E. Black of N.W. Harris and Co. Bankers of New York

Letter to W.D. Woodruff from E.E. Black of N.W. Harris and Co. Bankers of New York (1 page, printed), which accompanied a bill showing $10,000 due on the Dominion Power Company, July 23, 1907.

Letter to W.D. Woodruff from E.E. Black of N.W. Harris and Co. Bankers of New York

Letter to W.D. Woodruff from E.E. Black of N.W. Harris and Co. Bankers of New York (1 page, printed) regarding $41,000 in Dominion Power Company bonds that they have put in safekeeping, Oct. 30, 1907.

Letter to W.D. Woodruff from Mr. Harris of N.W. Harris and Co. Bankers of New York

Letter to W.D. Woodruff from Mr. Harris of N.W. Harris and Co. Bankers of New York (1 page, printed) which accompanied a receipt for the $41,000 Dominion Power Company bonds, Nov. 4, 1907.

Letter to W.D. Woodruff from E.C. Wheeler Jr. of N.W. Harris and Co. Bankers of New York

Letter to W.D. Woodruff from E.C. Wheeler Jr. of N.W. Harris and Co. Bankers of New York (1 page, printed) saying that he is pleased that Mr. Woodruff has decided to take the $10,000 Dominion Powers at 90 and interest. They will expect Mr. Woodruff in a few days, Dec. 10, 1907.

Receipt from N. W. Harris and Co., Bankers, New York

Receipt from N. W. Harris and Co., Bankers, New York for installment on Dominion Power and Transmission Co., Dec. 19, 1907.