The strength training zone requires you to use loads in the range of 60% to 100% of 1RM. The relationship of percentage loads to number of repetitions (rounded up) to failure are as follows:
• 60% - 17 reps
• 65% - 14 reps
• 70% - 12 reps
• 75% - 10 reps
• 80% - 8 reps
• 85% - 6 reps
• 90% - 5 reps
• 95% - 3 reps
• 100% - 1 rep