( ( Muscular strength ) ( ( is ( ( the ability ) ( of ( a ( muscle ( to ( ( ( ( exert force ) ( for ( ( a ( brief period ) ) ( of time ) ) ) ) , ) ( while ( ( muscular endurance ) ( is ( ( a ( muscle 's ) ) ( ( ( -LRB- ( or ( ( group ( of ( muscles ' ) ) ) -RRB- ) ) ) ability ) ( ( ( to ( sustain ( repeated contractions ) ) ) or ) ( to ( continue ( to ( apply ( force ( against ( a ( fixed object ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (JJ Muscular) (NN strength)) (VP (VBZ is) (NP (NP (DT the) (NN ability)) (PP (IN of) (NP (DT a) (NN muscle) (S (VP (TO to) (VP (VB exert) (NP (NN force)) (PP (IN for) (NP (NP (DT a) (JJ brief) (NN period)) (PP (IN of) (NP (NN time))))) (, ,) (SBAR (IN while) (S (NP (JJ muscular) (NNS endurance)) (VP (VBZ is) (NP (NP (DT a) (NN muscle) (POS 's)) (PP (NP (PRN (-LRB- -LRB-) (CC or) (NP (NP (NN group)) (PP (IN of) (NP (NNP muscles) (POS ')))) (-RRB- -RRB-)) (NN ability)) (NP (S (VP (TO to) (VP (VB sustain) (NP (VBN repeated) (NNS contractions))))) (CC or) (S (VP (TO to) (VP (VB continue) (S (VP (TO to) (VP (VB apply) (NP (NP (NN force)) (PP (IN against) (NP (DT a) (VBN fixed) (NN object))))))))))))))))))))))) (. .)))
Muscular strength is the ability of a muscle to exert force for a brief period of time, while muscular endurance is a muscle's (or group of muscles') ability to sustain repeated contractions or to continue to apply force against a fixed object.
(ROOT (S (NP (NP (NNP Strength)) (, ,) (NP (NP (DT the) (NN ability)) (PP (IN of) (NP (DT a) (NN muscle) (S (VP (TO to) (VP (VB use) (NP (NN force)) (PP (IN during) (NP (DT a) (NN contraction))))))))) (, ,)) (VP (VBZ differs) (PP (IN from) (NP (NNP endurance))) (, ,) (S (VP (VBG meaning) (NP (NP (DT the) (NN ability)) (PP (IN of) (NP (DT a) (NN muscle) (S (VP (TO to) (VP (VB continue) (PP (TO to) (NP (NP (NN contract)) (PP (IN over) (NP (NN time))))) (PP (IN without) (S (VP (VBG getting) (ADJP (JJ tired)))))))))))))) (. .)))
Strength, the ability of a muscle to use force during a contraction, differs from endurance, meaning the ability of a muscle to continue to contract over time without getting tired.