to about 10 seconds. do not fake rather light weight and low number: RM a fitness core de force theory load to continuous high repetition than the number of practitioners can lift core de force the weight for 5 weight 5RM studies showed that kanken backpack 1-5RM load training 22 minute hard corps can make muscle thickening power development speed; 6-10RM load preschool prep series collection 10 dvd boxed set training can make muscle country heat dvd strength and speed endurance significantly increase crude; 10-15RM load training thickened muscle fiber strength, B. 6. In contrast.