Estimation Of 1-RM from Isometric Maximal Voluntary Contraction in the Weight Training Machine with Healthy Male Adults

Abstract

PURPOSE: To estimate 1-RM by isometric maximal voluntary contraction in the weight training machine with healthy male adults. untimately, to find indivisual weight training intensity easily by portable computerized Isometric muscle strength testing machine attached to general weight training machine. METHODS: In this study, fifty healthy male adults(34 ± 5.3yrs) were performed isometric maximal voluntary contraction in eight weight training machines(leg extension, leg curl, chest press, shoulder press, abdominal curl, arm curl, long pull, lat pull down) in starting position by using tensiometer(model JNB-500L of the JNB company)can be attached to different position. After 48 hours later, one-repetition maximum lift measurement were followed. RESULTS: Pearson correlation analysis indicated that correlation coefficient between Isometric maximal voluntary contraction and I-RM were 0.77 in Leg extension, 0.72 in leg curl, 0.84 in chest press, 0.82 in shoulder press, 0.71 in abdominal curl, 0.75 in arm curl, 0.57 in lat pull down, 0.55 in long pull, each of them. Multiple regression analysis Results indicated that regression equation of 1-RM leg extension could be estimated by Isometric maximal voluntary Leg extension contraction(R2=0.80), and other 7 position 1RM muscle contraction could be estimated same as leg extension (leg curl was R2=081; chest press was R2=084; shoulder press was R2=0.88; abdominal curl was R2=0.79; arm curl was R2=0.77; lat pull down was R2=0.67; long pull was R2=0.79). CONCLUSIONS: In conclusion, although correlation coefficients of Lat pull down and long pull were relatively low compared to other machines(r=0.57 and r=0.55 each), 1 -RM regression equation by isometric maximal voluntary contraction indicated relatively high R2 values. Also we thought that anthropometric mearsurements & exercise experiences might support higher R2