I am very confused in pull ups . When I started them they were really good . I got progress very quickly . In April I uses weights to do more pull ups .I do isometric holds . It was really good . In June was to do an isometric hold of 10 kg for 5 sets of 30 seconds . I was able to do 8 pull ups . But today I can do only 2 or 3 pull ups . I can still hold that isometric hold of 10 kg for 5 sets of 30 seconds . I can't understand the problem .