Yes, but the increase would be slightly above halfway between because the starting length of the spring would be greater.

I mean only one set. No separate warm-up sets or build-up sets are required. If done intensely enough one is all you need.

“The primary, on-going debate regarding the required volume of exercise for strength relates to the recommended number of sets. The ACSM [15] cited a meta-analysis [132, 133] suggesting that the largest effect sizes (ES) for strength increases with athletes occurred when performing 8 sets per muscle group. Carpinelli [19] considered this meta-analysis, criticizing the authors for the inclusion of studies that failed to meet their own criteria. In addition their conclusions were unsupported as there were no significant differences between the ES of the different training volumes. In fact, most research to date suggests that there is no significant difference in strength increases between performing single or multiple set programs [51, 134-137). For example, Carpinelli and Otto [134] found that single sets produced similar results in 33 out of 35 studies they reviewed.”

Fisher J, Steele J, Bruce-Low S, Smith D. Evidence Based Resistance Training Recommendations. Medicine Sportiva Med Sport 01/2011; 15:147-162.

No, because stimulation depends on recruitment, tension, and fatigue not length, and a muscle fiber can be recruited, produce tension, and be fatigued at any length.

There is no general physical fitness or functional ability benefit of training with sledgehammers that can not be obtained more safely and efficiently with the proper use of conventional free weights or machines. The only thing training with sledgehammers will do for you that proper training with barbells and machines won’t is improve your skill in the specific sledgehammer movements you perform, skill that does not transfer to other movements.

You’re welcome. While some equipment is better than others ultimately your results have far more to do with how you train than what equipment you use.

No matter what kind of exercise you do or how you do it you’re not going to burn enough calories for it to be worth worrying about. The role of diet is to create a calorie deficit, the role of exercise is to maintain or increase lean body mass while fat is lost.

As I mentioned in the article, the weight should be based on what you can use for the target rep range of 5 to 8, not a percentage of your one rep max.

I haven’t read the book, but it sounds like the doctor is really reaching to find a justification for his recommendations. While it doesn’t hurt to engage in light to moderately intense physical activity on a daily basis and there are health benefits to it, it isn’t necessary to do demanding physical activity or exercise (strength train) daily and it isn’t necessary to do any “cardio” if you are already strength training properly.

First, it is important to understand that HIT isn’t a program, it is a method which can be used to create a variety of programs based on individual goals and response to exercise. The method is the best for improving muscular strength and size and cardiovascular and metabolic efficiency, since it is consistent with the best evidence and the safest and most efficient in the long run. You wouldn’t need to alternate for strength and size versus conditioning, since if you are doing the workouts properly you will simultaneously effectively stimulate improvements in both.

The effectiveness of an exercise depends far more on the effort you put into it than how much weight you use, and there are many ways to increase the effort required other than adding weight. Increasing the time under load by slowing the reps down and/or increasing rep count is one way to do this, and most people will also find improvements in exercise form can make a huge difference in exercise difficulty. Most people’s form is so inefficient for the real goal of exercise (working the muscles intensely rather than just moving weight up and down) that when they are taught to perform exercises correctly they must cut the weight by half or more of what they would normally use.