Task Specific Strength Chapter 2 How, What and Why? How to train What should be trained Why training should be performed What is strength? How is it achieved? Task specific strength has carryover Elements of Strength Maximal muscular performance Pm, Fm & Vm Parametric relation between these variables? 1RM or personal best Negative relationships Force/velocity relationship? http://www.scripps.edu/cb/milligan/projects.html Figure 2.1 – 1969 Table on page 19 Nonparametric Relations Maximum maximorum performance Only max under favorable conditions Pmm, Fmm & Vmm Relation between Pm and Pmm is nonparametric Nonparametric are positive Nonparametric cont… Greater Fmm and Vm WHY? Stronger and faster Resistance must be sufficient to allow strength to be manifested If force is low then strength plays no role What sports? Training should include both Example on page 21? Figure 2.2 max force and specific velocity Defining Strength Ability to produce Fmm Concentric – shortening against force Eccentric – lengthening with force Isometric – no change with force Fmm must be against high force Extrinsic Determining Factors Mechanical feedback – effect of the outside forces Force applied causes a change Types of resistance Elastic – force is pos related to distance of stretch Inertia – F = MA Hydrodynamic – viscosity Compound resistance – weights and chains or elastic Intrinsic Determining Factors Rate of force development (RFD) – time for force to be manifested Time to peak force Tm Time to peak force is 0.3-0.4 s Figure 2.8 Explosive strength deficit 50% Figure 2.8 Finger snap (force accumulation) Table on page 27 – compare? Explosive Strength Deficit May increase Fmm May increase RFD with explosive work Strength and power are different S gradient on page 28 Figure 2.7 - 0.3-0.4 s Figure 2.9 Velocity Inverse relationship AV Hill equation on page 30 Intermediate range is important Max power is at 1/3 why? (pg 31) Shot putters vs. javelin throwers? No relationship between Fmm and Vmm Figure 2.10 Figure 2.13 P=w/t or FxV Eccentrics Much greater than concentric Why? Total force velocity curve Fewer muscle fibers and EMG DOMS and damage Figure 2.14 Stretch-Shortening Cycle (SSC) Eccentric-concentric couple Countermovement jump Elasticity – stretch induced – what formula? Stiffness Muscle – variable Tendon – constant Tension and stiffness are related Acts like rubber band – Figure 2.15 Neural Mechanisms Muscle spindles – stretch Golgi tendons – force Neural loop – reflex Training enhances this effect Figure 2.19 (read top pg. 39) Strength Curves Strength changes as a function of ROM Why is this important for lifting? Overlap? Length tension curves Torque=fd (d=moment arm) Lever changes and force changes Figure 2.21 Figure 2.22 Levers and Strength Strength = force moment arm ratio Short levers create more force Line of force action is close to joint when force is high Figure 2.26 Summary Parametric relations are negative Nonparametric may be positive Max force equals strength External factors such as type of resistance Time of force production RFD is important (isometric) Strength and power are different Concentric vs. eccentric strength SSC reactive strength Elastic and neural Spindles vs. golgi Length tension Lever length Next Class Lab tonight on VJ force, velocity and jump height (CMJ vs SJ) and unloaded knee extension velocity (R vs L) Homework explanation Read Huxley article and write synopsis Next week Chapter 3 and lab