抵抗力弱 weakened immune systems

心力弱竭 Heart failure ; cardiac failure

视力弱 dysopsy ; weak eyesight

表达能力弱 Weak ability to express

战斗力弱 low combat effectiveness

能力弱 poor in quality, ability, etc

自制力弱 impulsive

一时之强弱在力，千古之胜负在理 Temporary victory may be determined by one's might; but lasting victory is determined by whether one has justice on his side.

力量、势力减弱 impair ; weaken ; cripple

无力的衰弱的 enervated