Today's guest blog post comes from Spain - Carlos Balsalobre-Fernández, a sport scientist and strength & conditioning coach to many elite Spanish runners. This guy is bright, he even developed his own iPhone app to measure jump height - so keep reading! Carlos is going to cover an interesting topic, velocity loss from the fastest to the slowest rep of a set. He'll share the facts today and help us understand how to interpret velocity loss based on our training goals.
How many reps should I perform in each set today? Do I need to leave some reps in the tank, or should I do as many as possible? Everyone familiar with resistance training has asked themselves these questions about training prescription. Traditionally, resistance-training programs have been prescribed using the well-know RM methodology. For example, you might have performed 4 sets at 10RM (i.e. a load that enables you to do no more than 10 reps) for an exercise. Why? There ‘seemed’ to be a good relationship between the number of reps that can be performed at a certain load and the 1RM of the subject. If you could lift 70kg 10 times on the bench press exercise, it was believed that this load would represent about 75% of your 1RM. However, this methodology has two major drawbacks - first, the number of reps that can be performed with a certain %1RM can vary drastically between athletes of different specialties (for example, distance runners can perform almost twice as many reps with the same %1RM compared to weighlifters). Second, training with reps to failure might be a great stimulus to increase muscle hypertrophy, but it may produce too much fatigue that significantly decreases the neuromuscular and explosive performance of a subject. Using a certain RM to prescribe your training program is not as accurate as it was believed and could in fact make you less explosive and powerful.
To address these limitations, recent studies have analyzed the relationship between movement velocity and %1RM for different exercises. The result - movement velocity can predict, in a highly accurate way, the training intensity (i.e. %1RM) and the maximum strength capabilities of a subject without the need to perform reps to failure or 1RM tests. Moreover, Sánchez-Medina and González-Badillo demonstrated that controlling the decline of velocity during a set with exercises like the bench press or the back squat, is a great way to assess fatigue from a training stimuli. Essentially, they observed that performing reps to failure, irrespective of load used, produces a decline in velocity of about 40-60% (i.e. the difference in % loss between the fastest and the slowest rep of a set). Similarly, they found that performing just half of the reps that can be done with a certain load produces a velocity loss of about 20-25%. Therefore, controlling the velocity loss during resistance training can help you understand your level of effort and can provide you recommendations regarding how many reps to perform based on your training goals. For example, if you just want to focus on gaining muscle mass, you should train with a reps to failure approach, meaning, you need the loss in velocity to be about 45% or more; if the loss is around 20%, you would need to do more reps! Alternatively, if you want to develop your speed and power capabilities (i.e., jumping, sprinting, throwing…), you would try to perform the number of reps associated with a 20% loss or less; if there was a 35% loss from the fastest to the slowest rep, you performed too many. You’d know that the next set requires fewer reps.
This velocity-based training methodology (VBT) is becoming more popular (and effective) since it provides a better understanding of our resistance training programs that optimize adaptations. Remember, not everybody should perform reps to failure, but an optimal amount to maximize specific gains!
1. Richens B, Cleather DJ (2014) The relationship between the number of repetitions performed at given intensities is different in endurance and strength trained athletes. Biol Sport 31: 157–161.
2. Izquierdo M, Ibañez J, González-Badillo JJ, Häkkinen K, Ratamess NA, et al. (2006) Differential effects of strength training leading to failure versus not to failure on hormonal responses, strength, and muscle power gains. J Appl Physiol 100: 1647–1656.
3. Sanchez-Medina L, Gonzalez-Badillo JJ, Perez CE, Pallares JG (2014) Velocity- and power-load relationships of the bench pull vs. bench press exercises. Int J Sport Med 35: 209–216. doi:10.1055/s-0033-1351252.
4. Sanchez-Medina L, González-Badillo JJ (2011) Velocity Loss as an Indicator of Neuromuscular Fatigue during Resistance Training. Med Sci Sport Exerc 43: 1725–1734.