Don't be competitive. Great athletes are born, not made. Focus on form, not weight. Don't hurt yourself.
Single set training does not necessarily mean doing one and only one set. In my opinion, it means doing one, and only one, 100% intense set per exercise. This means you lift a given weight as many times as you possibly can in good form. If you could have done one or more additional repetitions, then you did not work at 100% intensity. This is a lot harder than it sounds.
However, I find that I am not always 100% mentally and do not reach the required level of intensity, and so I attempt a second set to 'failure' (but never a third). It is important to note that doing more than one 100% intense set results in significant diminishing returns with each subsequent set and can easily lead to overtraining.
If I train once a week, then I maintain my strength. If I train twice a week, then I get stronger. If I train three times a week, or more, then I will overtrain, and get weaker.
Under no circumstances no more than sixty minutes a day, three non-consecutive days a week, should weight training be performed. To reiterate, this is the upper limit in terms of frequency and duration for H.I.T., and you will likely find that you are unable to train at your highest intensity for that long and that frequently without the risk of overtraining. Personally I optimally train at twenty-five minutes a day, two days a week. Most exercises I only do once per week. This is apart from any aerobic activity.
While failure can be achieved at any repetition range, doing fewer repetitions with more weight is often easier for me (though admittedly not as safe). But in most cases, I would recommend choosing a weight you think you can do at least six times. Stick with that weight until you can do it ten times, and then increase the weight by at most five percent. Rinse and repeat.
You can work out as hard as you want, but if you don't get enough rest, it will be for nothing. Rest is as important as, and should be proportional to, intensity, and, contrary to popular belief, as you get stronger you will need more time between workouts.
If you trained intensely, and you rested for n days, then trained again but did not get [slightly] stronger, then you should increase the number of days between workouts until you start getting results. You must allow enough time for your body to adapt. Do not be afraid to take a two-week break.
The lower number tiers have higher priority than the higher number tiers. This means that in order to do exercises in tier three, one must also do the exercises in tiers one and two. If there is more than one exercise within a tier, then all exercises in the tier must be done. It is not suggested that one perform all the exercises listed here during a single workout.
Deadlifts is the foundation for all other exercises (e.g. reduces the risk for injury). It works more muscle groups than almost any other exercise. It also encourages correct posture. Half deadlifts are beneficial and are sometimes more appropriate.
Squats. It's difficult to say which works more muscle, deadlifts or squats, but it is generally accepted that doing squats helps you get more muscle everywhere, not just the lower body.
One set only, no rest between exercises.
One set only, no rest between exercises.
Tiers one through three include the exercises that the body is strongest at. These exercises work the largest amount of muscle in the body.