Has your normal strength training routine gone a bit...stale? Tired of putting in hours at the gym but not getting the expected results? It could be time to ramp up your workouts with high-intensity training, or HIT.|
Originally developed in the 1970s by trainers and coaches of professional athletes, HIT is a specialized approach to strength training that has shown to provide better results in less time and with less risk of injury. These perks make HIT suitable for many people, including non-athletes and those simply trying to lose weight and become more fit, regardless of age or gender.
HIT is demanding, both physically and mentally. As with any form of high-intensity exercise, you need to be in good basic health and free from any significant cardiovascular risk factors and muscle or joint problems that could limit your capacity to exercise safely at a more demanding level. If you have any doubts or concerns, consult your doctor before trying any of these techniques.
Principles of HIT
So, how exactly does HIT differ from traditional strength training? There are two primary differences.
1. The Secret to Achieving Perfect Form
While traditional training methods focus on the quantity of repetitions (eight to 15), sets (two to three), and weight lifted, HIT focuses on quality: form. By using ideal form, you can achieve better and faster improvements in strength and muscle growth with just one set of exercises for each muscle. Proper form and fewer sets virtually eliminate many of the injury risks associated with multiple sets that are performed with less than ideal form.
The basic characteristics of a "perfect" HIT repetition/set include:
Slow, controlled movement. Without bouncing or using momentum, take two to three full seconds to lift the weight (positive phase). Before lowering the weight, pause for half a second and squeeze the contracted muscle. Finish one rep by taking four to five full seconds to lower the weight to the starting position (negative phase). The key here is to keep the muscle under constant tension, without allowing the weight to rest on the machine or on your body at the bottom of the negative phase.
Full range of motion. Each exercise should be taken through the complete range of joint movement, but don't fully straighten or "lock out" your joints.
Momentary muscle fatigue (MMF). The goal is to feel the burn in the target muscle by the end of your set, without sacrificing ideal form. You will defeat the purposes of HIT by arching your back, rocking your body or using momentum to squeeze out another repetition or two. You will also limit training effectiveness by stopping at a predetermined number of repetitions per set if you could do more without sacrificing form.
You're doing it right if the target muscle is trembling, shaking and burning during your last repetition. Pain in a joint or a non-target muscle is usually a red flag that your form is wrong. Implementing the perfect form principle is mainly a matter of focus and concentration. You need to pay close attention to the “rules” of good form at all times during your workout (including proper breathing and body position) and to your timing.
2. The Triple Progressive Overload Principle
Traditional weight training relies on a “double progressive overload principle," which involves progressively adding weight and increasing the number of repetitions to keep overloading the muscle and produce improvements in strength and size. HIT adds a third factor to this equation: increasing the time spent with the muscle under constant tension.
Depending on your individual genetic potential, you can train your muscles to produce maximum power for up to three to five minutes at a time. To accomplish this, you need to keep increasing not only the amount of weight and number of repetitions you can lift, but also the total amount of time that your muscles are under continuous tension during each set and each workout session. The best way to implement the triple overload principle will vary depending on your training goals and priorities. Competitive weightlifters, bodybuilders and endurance athletes all need specialized approaches based on the requirements of their sports.
General HIT Guidelines
If you're pursuing modest or general fitness goals, follow these strategies:
Warm up. Begin each HIT session with a five-minute cardio warm-up and a brief static stretch for each muscle group that you will work.
Pick the right starting weight. For each exercise in your routine, start with a weight that allows you to reach momentary muscle fatigue in eight repetitions, using perfect form and the six to eight second cadence described above.
Ramp up the reps. For subsequent workouts, aim to increase the number of repetitions you can do, using the same six to eight second cadence for each repetition, until you are able to do 15 repetitions with perfect form (a total of 90 to 120 seconds of continuous muscle tension for each set).
Ramp up the weight. Once you can do this reliably, increase the weight you lift by five to 10 percent and repeat this process, starting with as many perfect reps as you can do and increasing the reps until you are doing 15 of them total.
Only increase one thing at a time. Each successive workout should provide at least the same and preferably more overload (i.e. more weight, more reps or more total time under tension) than the previous workout, but only one of these factors should be changed at once. In theory, you can achieve the benefits of HIT by performing one set of each exercise, as long as you reach momentary muscle fatigue.
Rest between sets. 90 seconds of rest between sets is sufficient for beginners, but you can modify this to suit your training goals. Circuit training, for example, will add an aerobic component to your workout, while five minutes of rest may be ideal for power lifters using heavier weights.
Recover after workouts. Since HIT induces complete muscle fatigue, it's crucial to allow adequate time for recovery and rebuilding of muscle tissues between sessions. At a minimum, allow 48 hours between sessions training the same muscles. For most people, 72 or even 96 hours may produce better results.
Cool down. After each workout, take at least five to10 minutes for a light aerobic cool down. Finish with another round of static stretches for the muscles you worked to enhance recovery and reduce the risk of injury.
Everyone, from marathon runners to competitive power lifters to 58-year-old guys trying to stay in shape, can use HIT to achieve their goals, but you may need to adjust the general approach to suit your needs. If you’re interested in HIT, I highly recommend the book, "High Intensity Training" by John Philbin. Also, check out our related article about high-intensity interval training.