The Relationship of Strength and Body Composition to Vertical Jump Ability in Division 1 Female Volleyball Players.

Jump ability is important in volleyball; therefore analysis of factors that influence jump performance is necessary to ensure maximal jump ability. Purpose: To analyze how strength characteristics associated with jumping are affected by percent body fat, lean body mass and free fat mass. Methods: Data from eleven female NCAA DI volleyball players as part of an ongoing athlete monitoring program collected from 2007-2010 was analyzed. Data was separated into weakest and strongest based on isometric peak force allometrically scaled. In all cases the weakest data corresponded to testing during the athletes first year at ETSU. Body composition was measured using air displacement plethsmography (BodPod). Maximum strength (isometric peak force – IPF) and strength characteristics (peak force -F@ 50ms, 90ms, and 250ms; rate of force development, 0-200ms –RFD) were measured with isometric mid-thigh pulls on a force plate, and countermovement jumps with 0, 11 and 20 kg . Allometric scaling of the different force values (IPFa, F@50a, F@90a, F@250a) was used to normalize differences in the body mass of the athletes (absolute force/ (body mass (kg0.67)). Pearson correlations were used to determine the relationship strengths. Results: In weaker test results, there are moderate and small inverse correlations between CMJ and PF (r=-0.34) and PFa (r= -0.19), and strong inverse correlations between CMJ and percent body fat (r=-0.67). In stronger test results there are small correlations between CMJ and PF (r=0.23), PFa (r= 0.26), and moderate inverse correlations between CMJ and percent body fat (r=-0.40). There is a significant change in jump ability and strength between both groups. Conclusion: As an athlete becomes stronger, there is a significant correlation between CMJ strength, PF, PFa, F250, and F250a. The relationship between CMJ and strength characteristics decreases as BF increases

Tritium exchange reactions catalyzed by 2-oxo-4-hydroxyglutarate aldolase from Escherichia coli K-12

Tritiated water and tritiated substrates have been used to study exchange reactions catalyzed by Escherichia coli 2-oxo-4-hydroxyglutarate aldolase (4-hydroxy-2-oxoglutarate glyoxylate-lyase, EC 4.1.3.16, 2-oxo-4-hydroxyglutarate [right harpoon over left] pyruvate + glyoxylate). With pyruvate, the enzyme catalyzes a rapid first-order exchange of all three methyl hydrogens in the absence of added acceptor aldehyde (i.e. glyoxylate). This reaction is not rate limiting for aldol condensation or cleavage; quite different pH-activity profiles for the exchange reaction versus aldol cleavage and also comparative effects that pH changes have on Km and V values for the two processes favor this conclusion. The exchange reaction with 2-oxobutyrate, a substrate analog, is stereoselective; one methylene hydrogen is removed at a 6-fold faster rate than the other but eventually both are exchanged. No tritium exchange occurs with glyoxylate.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/23566/1/0000526.pd