As a general rule of thumb, the higher the total time under tension, the greater the impact on body composition. This is due to greater metabolic adaptations associated with increased time under tension. In order for an athlete to maintain control over a weight for a prolonged period, he/she must sacrifice on the intensity of the set (weight on the bar). This has a knock on effect of potentially reducing the strength training effect. Heavier weights will be required to optimally develop maximal strength, and particularly so to develop relative strength, therefore lower prescriptions for total time under tension must be applied. It is possible to have repetitions with a tempo for each rep totalling over 10secs (e.g 80X2), while still delivering a great strength training effect. However, in these cases the reps must be much reduced due the challenge presented by the intensity/weight, most likely only 1-3 repetitions per set.
HOW TRAINING OBJECTIVE DETERMINES TEMPO, TUT & REPS
EXAMPLE 1: RELATIVE STRENGTH (ADVANCED LIFTER)
When training for relative strength (maximal strength gain with minimal or no bodyweight gain – e.g. boxing/mma), provided the athlete has a strong strength training history, the total time under tension should not exceed 20-25 seconds per set. This strength quality is largely dependant on strength training methods where the aim is to improve motor unit recruitment and firing rate. The intensity required for these methods is typically in the 85-100% of 1RM (maximal weight that can be lifted for one repetition), and the range in repetitions will usually fall between 1-5 per set. Depending on the stage of training the athlete is at within their overall plan, their training on strength lifts could look like any of the following examples:
4 sets of 5 repetitions @ 85%. Tempo: 40X0 (24 seconds TUT)
8 sets of 2 repetition @ 90-93%. Tempo: 62X0 (16 seconds TUT)
3 sets of 3 repetitions @ 87-90%. Tempo: 30X0 (9 seconds TUT)
Each of the above examples will achieve the objective of a total time under tension of <25seconds, intensity > 85% 1RM, and a repetition range between 1-5.
Its important to note here that none of these methods would be used for a very long period of time. Variation is hugely important for long term strength development, and in general, more advanced athletes require even more variety.
Its possible to alternate between phases of relatively intensive phases with lower TUT, to extensive phases with reduced intensity and higher TUT, while staying within the parameters associated with the overall training objective.
EXAMPLE 2: ABSOLUTE STRENGTH
When training for absolute strength (maximal strength development irrespective of bodyweight gain – e.g. Rugby prop), the total time under tension will generally fall somewhere between 20-40 seconds but may be more or less depending on the sport and/or training priority.
The intensities used for these methods is typically in the 70-90% range of 1RM, and the repetition bracket is generally 5-8 per set. Again, depending on the stage of training the athlete is in within their overall plan, their training on strength lifts could look like any of the following examples:
3 sets of 8 repetitions @ 75%. Tempo: 40X0 (40 seconds TUT)
5 sets of 5 repetition @ 80-85%. Tempo: 32X0 (30 seconds TUT)
4 sets of 7 repetitions @ 80%. Tempo: 30X3 (48 seconds TUT)
Each of the above examples will achieve the objective of a total time under tension between 20-40seconds, intensity > 70% 1RM, and a repetition range between 5-8 per set.
Of course, there are many other factors which must be considered when designing a complete training program. Of most importance is the athletes training history and exposure to high loads and volumes of strength training. The exercise, variation type and range of motion all further influence the tempo prescription and therefore the number of repetitions required.
After reps, the next variable to be decided on is the optimal number of sets.