1) Tension development during rapidly grip strength exertion of athletes and nonathletes was by Natori's method analyzed.<BR>2) Subjects of athletes were 71 healthy men of 17-26 ages and of non-athletes were 54 healthy men of 17-30 ages. Athletes were 26 high school students of 17-19 ages, 22 physical education college students of 19-21 ages and 23 general adult men of 20-26 ages. High school students were 3 Sumo-men, 4 Judo-men, 6 Kendo-men and 13 Baseball-men. Physical education college students were 6 Handball-men, 9 Rugby-men and 7 Gymnasticsmen. General adult men were 11 Judo-men and 12 Kendo-men. Non athletes were 20 high school students of 17-18 ages, 6 university students of 19-21 ages and 28 general adult men of 21-30 ages.<BR>3) Isometric grip strength manometer were used a new device, to improvement on Smedley's manometer straingauge added.<BR>Tension development were amplifired and recorded by portable Visigraph (Sanei-Sokki Ltd.) with paper-speed of 10cm/sec.<BR>4) In the each case was 3 portions of a whole curve of time course of tension and Pmax.P₁, P₂; log t₁, log t₂; tan θ, tan ψ estimated according Natori's method.<BR>5) Except general adults of 26-30 ages of non-athletes were Pmax. of athletes greater than non-athletes.<BR>Pmax, of a Judo-man of general adult was greatest 68.5kg, and Pmax. of a high school student of 17 age of non-athlete smallest 35.8kg.<BR>6) Tan θ and tan ψ of athletes were greater than non-athletes.<BR>Tan θ of a Sumo-man of high school student was greatest 0.3628 and tan θ of a Judoman of general adult was greater 0.3500, but tan θ of a high school student of non-athletes was smallest 0.1624.<BR>Tan ψ of a Kendo-man of general adult was greatest 1.6308 and tan ψ of a Sumoman of high school student was greater 1.5769, but tan ψ of a high school student of non-athlete was smallest 0.5278.<BR>7) Muscle strength of non-athletes may well increased to be about 25 age, so that Pmax. of general adults of non-athletes were greater and of high school students of nonathletes smaller.<BR>But athletes exercised usually for athletic sports, so that Pmax, and tan θ, tan ψ independent of age was greater than non-athletes, these were an each event varied. Pmax. of Judo-men of general adults were relative greater and tan θ, tan ψ were greatest. Pmax. of Handboll-men were greatest but tan θ, tan ψ were relative smaller. Pmax. of Gymnas-tics-men were relative greater but tan θ, tan ψ were smallest. So that were varied pattern of time course of tension development of hand grip exertion an each event of athletics.