What determines mechanical tension during strength training? Given the compelling evidence of a dose-response relationship between volume and hypertrophy (4), it remains questionable whether the heightened anabolic signaling was due to a longer TUT or simply the greater amount of total work performed. The recruitment of low-threshold motor units does not stimulate very much muscle growth, because such motor units govern only a small number of relatively unresponsive muscle fibers. Check it out. Vertical jumping programs do not cause meaningful hypertrophy, although high-velocity movements involve very high levels of motor unit recruitment. There are a number of ways to implement the higher TUT sets: The options are many and your decision should really come down to individual goals and preferences. While mechanical tension is indisputably a primary major driver of muscle growth, there's compelling evidence that a significant exercise-induced metabolite buildup plays a role as well (11). When lifting light or moderate loads with a submaximal bar speed, fatigue increases the level of motor unit recruitment, activating new muscle fibers, which compensate for the reduced force produced by previously activated, but fatigued fibers. It just so happens that my lab carried out a study that sheds light on this very topic. It takes two seconds to lift the weight and two seconds to lower it. Think foam rolling hurts? Conceivably, the combination of these factors would have an additive effect on muscular development, increasing gains over and above what can be achieved when one factor is high and the other is low. Single vs. multiple sets of resistance exercise for muscle hypertrophy: a meta-analysis. Cheloveka 35: 97-102, 2009. This means that the definition needs to refer to: (1) which muscle fibers are being subjected to tension, and (2) the level of tension that is applied, by reference to the speed that the muscle fibers are shortening. De-stress and take the edge off without feeling drugged. How should we train the pectoralis major? Therefore, if we do not word our definition of time under tension to refer to *which muscle fibers* are subjected to tension, then we might wrongly assume that endurance exercise involving slow movement speeds would produce a lot of hypertrophy in the muscle fibers controlled by low-threshold motor units. Cutting edge new data from the Journal of Physiology (J. Physiol 590.2, pp. Yes, you need more than the big three, especially to prevent elbow pain. Rather, it's more appropriate to consider the total TUT performed for a given muscle group in a given workout. How much muscle can an advanced, natural lifter gain in middle age? Motor units control the production of force in much the same way during all types of muscular contractions, regardless of whether these contractions are classified as strength training or aerobic exercise. Ross. Learn all about testicles and be the life of the party or, alternately, be shunned by everyone there. Fortunately, we can look to longitudinal training studies that actually measure muscle hypertrophy for answers. Here's something that will do just that. Hulmi, JJ, Walker, S, Ahtiainen, JP, Nyman, K, Kraemer, WJ, and Hakkinen, K. Molecular signaling in muscle is affected by the specificity of resistance exercise protocol. Long distance running reduces the size of muscle fibers of all types, despite involving a very long duration of time under tension for the fibers governed by low-threshold motor units. You can combine strategies into a single workout, with compound exercises such as squats, presses, and rows devoted to lower TUTs and single-joint accessory movements focused on higher TUTs. Emerging research out of Russia shows that this indeed is the case, with light-load protocols involving high TUTs (50% 1RM) showing more type 1 fiber growth and heavier-loads with lower TUTs (80% 1RM) displaying greater hypertrophy of type II fibers (7, 8, 10). Vince Gironda was a legendary bodybuilding coach, and you can still learn a lot from him today. Hormonal adaptation determines the increase in muscle mass and strength during low-intensity strength training without relaxation. Not to be confused with super sets, these smart compound sets will blow up your chest, shoulders, legs, and triceps. This will in basically leave time under tension similar between a normal cadence. This occludes circulation to the muscle, creating a hypoxic environment similar to blood flow restricted exercise. Can. When lifting heavy loads (equal to or heavier than 5RM), lifting a weight with either maximal or submaximal effort does recruit high-threshold motor units and involves a slow fiber shortening speed. Occup. Physiol. Our new definition only includes the amount of time for which fibers of high-threshold motor units are subjected to the level of mechanical loading that results from them shortening slowly. A key point here is that we equated volume-load between groups and therefore total TUT for each exercise was roughly equal across conditions. For example, doing a slow set of 10 reps will have a longer time under tension as compared to 10 FAST reps. Again, why is this important? To achieve this high force, a fiber needs to contract actively at a slow speed, because the shortening speed of a fiber is the main determinant of the force it produces. Only those contractions that involve the recruitment of high-threshold motor units while muscle fibers are shortening slowly will stimulate meaningful amounts of hypertrophy. When lifting light or moderate loads, using a submaximal effort (a slow tempo) does not recruit high-threshold motor units. Mechanical loading can account for all of the results that have been reported to date. There's a better exercise to build your back. Physiological effects of using the low intensity strength training without relaxation in single-joint and multi-joint movements. Hypertrophy is mainly the result of single muscle fibers inside a muscle increasing in volume. Therefore, the duration of stimulating time under tension is very similar. Especially if the normal cadence is lifting with maximal intended velocity, as this will aid in getting additional reps, further compensating for the decreased time under tension. The effect of training volume and intensity on improvements in muscular strength and size in resistance-trained men. Time under tension is another one of these methods, but it really only came into prominence fairly recently… Basically, time under tension has to do with specifically varying the tempo of your workouts; the length of time that you take to do each rep. Therefore, muscle fiber shortening speeds are slow, and this allows a fairly high force to be produced by each working fiber. Again, in those rare cases where an extremely slow tempo is used, and the resulting bar speed in the final reps of a set to failure differs substantially from the bar speed achieved during these reps when applying maximal effort, this extremely slow tempo will necessarily involve fewer reps being done before failure, and this will broadly equate the stimulating time under tension. The researchers randomized well-trained male subjects to perform a routine consisting of either 4 sets of 10-12 reps or 4 sets of 3-5 reps. Here are the facts. (1985) , 2014. When a fiber shortens more slowly, each of its crossbridges can remain attached for longer, and this increases the amount of force it can exert. Research has reported a dose-response relationship between training volume and hypertrophy, but no such relationship between lifting (concentric phase) tempo and muscle growth, despite tempo being a very effective way for increasing the duration of time spent performing a set of a strength training exercise. Lower leg high-intensity resistance training and peripheral hemodynamic adaptations. The general consensus is that increasing TUT will maximize hypertrophy. Fiziol. J. Appl. Thus, sets of long durations will necessarily involve lower levels of tension than those of shorter durations, assuming training is carried out near or to momentary muscular failure. Women may need longer TUT than men to build muscle. And it delivers, every time. Only in the final reps, when bar speed has slowed down in the fast tempo set, and when motor unit recruitment has increased in the slow tempo set, is muscle growth stimulated. Cheloveka 32: 121-127, 2006. Perform. I. M. Sechenova. Therefore, time spent doing these reps cannot be counted as stimulating time under tension. From a practical standpoint, the evidence indicates that adding in some high-rep sets with a TUT of around 60-90 seconds (20-30 RM per set) can be beneficial if your goal is maximal hypertrophy.