Discussion: Novel data from our study show that 30-s prone back extension repetition maximum can predict 1RM of concentric and eccentric squat strength in young and older adults. respectively. Thus. clinicians and rehabilitation professionals can use our novel equations to design concentric- and eccentric-biased resistive training programs in young and older adults. https://www.nacrack.com/best-buy-Fleshlight-Universal-Launch-Auto-Stroker-amazing-offer/