Training: Repetition speed, time, and cadence x3|
August 7, 2001
|Certification for Active Minds
International Association of Resistance Trainers
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Speed refers to the distance traveled by a body per unit time. Time provides a measurement of a period during which an action, process or condition exists or continues to exist. Together, distance and time provides the basis for an exercise?s cadence, being the beat, rate, or measure of any rhythmic movement.
Two common cadences include the Nautilus protocol of 2 seconds on the positive and 4 seconds on the negative, and the Super Slow protocol of 10 seconds on the positive and 5 seconds on the negative.
The ideal cadence, as with any aspect of an exercise program, must be individually prescribed, with each exercise?s time being reflective of limb length, range of motion, and even neurological efficiency (some people cannot move very slow without segmenting repetitions in a jerky manner).
Discovering ideal cadences require some investigation and experimentation. First, the weight must be moved properly, which means slow and controlled. Hence, when lifting a weight, generate only enough muscular force until it begins to move. From that point, continue producing only enough force to keep the weight moving slowly and smoothly without perceivably increasing speed. Once at the top, i.e., the exercise?s most contracted position, pause briefly for one second or less and only long enough to reduce the level of force so the weight begins to reverse directions downward, resulting in a smooth and deliberate turnaround. If the exercise offers an intense contraction (e.g., calf raises), then the top position can be held longer to increase muscular inroading, with 2-3 seconds being reasonable.
(Two words must be defined at this juncture: smooth and slow. Smooth means ?of uniform consistency, without abrupt jerking or stopping.?
Slow refers to a speed that permits such smooth movement. Consequently, ballistic and explosive movements are not slow since the action begins with an abrupt start, and if continued quickly, results in an abrupt stop at the top of the movement. Likewise, dropping a weight quickly to the bottom position is neither smooth nor slow since it, likewise, results in an abrupt stop.)
Record the time of each repetition for each chosen exercise within the program?s prescription, or divide the set?s total tension time by the number of repetitions. Do so for at least two workouts to discover the ?average? timing of the repetitions for each particular exercise. Considering muscles are strongest on the negative, thereby possessing greater control, expect the negative phase to be slightly slower than the positive phase.
What constitutes a comfortably slow and smooth movement for each exercise is correspondingly the ideal repetition cadence of that exercise for that individual. Hence, each cadence then becomes the standardized unit of measurement for that exercise and for that individual. For person A, the ideal bench press timing may be 5 seconds up and 7 seconds down, and for person B it may be 4 seconds up and 4 seconds down, depending on their relative sizes (e.g., height and limb length). Note that it is vital to perform this testing using ?typical? training poundages as there can be a significant difference if using 50% vs. 80% of a one repetition maximum; lighter resistance favors a much slower speed due to fewer physical demands and greater control.
You can then divide all muscle groups into short, medium, and long ROM categories, to have three standardized measurement times averaged out for various exercises. For example:
· Calf raises, wrist curls, and abdominal crunches could have a cadence of 4/4.
· Chest presses, arm curls, and bent barbell rows could have a cadence of 6/6.
· Pulldowns and pullovers could have a cadence of 8/8.
These are only examples, but they give you an idea of how to systematically work time values into a program without worrying about unique rep timing for each muscle or exercise.
By tracking repetition cadence you can determine, with accuracy, progress and overall value of a program. For example, consider a trainee who utilizes varying rep cadences within the same set, and if he were to stall on the 8th positive rep, completing only 7 to muscular failure at 60 seconds tension time. Next, consider if the trainee were to lift and lower the weight slightly faster in the next workout, completing 8 positive repetitions to muscular failure within 60 seconds tension time, then proceeded this with one last negative repetition for a total of 67 seconds. By his records, and the total tension time indicated, the latter set appears to be an improvement since it endured 7 seconds longer with the same resistance. However, the problem is that both workouts were not founded on equal ground, using different cadences, and they cannot be ideally compared.
In another example, if a trainee performed 10 repetitions with 100 pounds one workout, with a tension time of 60 seconds, then in the following workout performed 11 repetitions with 100 pounds, with a tension time of 66 seconds, then it can be deduced that the trainee improved. However, if the tension time remained at 60 seconds, yet the repetitions increased from 10 to 11, could it be said that improvement did, in fact, occur? Metabolically, performing more repetitions in the same period of time is different than performing less repetitions in the same allotted time; but to what long-term extent and effect is unknown.
(From my experience, and so long as all reps are safely performed, more repetitions per unit of time seem to have greater productivity in stimulating muscle hypertrophy, whether this is due to greater inroading, muscle fatigue, or tissue pump is unknown.)
One could argue either that a) the trainee did not improve ? since the tension time remained stagnant, or b) that he did improve ? since the number of repetitions increased. Regardless, if argued that he did improve, one could not quantifiably measure to what extent since the units of measurement (repetition cadence) altered from one instance to another.
To make the issue even more complex, a 3 second positive is less demanding than a 5 second positive with the same weight, even if aiming for the same tension time (obviously the number of repetitions will vary accordingly) since there is greater momentum with the faster speed. By not tracking the positive cadence, you may unintentionally expose the muscle to less tension, thereby making the set easier with the slightly faster speed.
Conversely, a slower negative ? slower than usual or prescribed as the individual?s benchmark ? makes work less demanding. Since lowering a weight is so much easier than lifting the weight, due to internal frictional forces, taking an additional 2-3 seconds to lower a weight affords repose, possibly allowing for enough recovery between repetitions to permit an additional positive rep on the last and final up-stroke.
Moreover, strength increases, and the ability to regularly improve in the number of repetitions performed, will be affected by the cadence and ROM of the exercise. For example, if using the same weight, it may take a few workouts to increase by one repetition if 10 seconds is the benchmark, but often only one workout if lifting for 4-5 seconds. With a 10-second repetition, it can take considerable effort just to make it halfway through the positive part of the stroke, indicating a full five seconds of additional tension time.
Considering the potential combinations reflective of slower repetitions, such data should be documented in a training journal.
In summation, to make precise comparisons, the workout itself must be regulated and standardized by utilizing equal units of measurement. This is not to say that one must measure everything, including repetition cadence to establish an effective program, but doing so increases accuracy ? an often lacking commodity in resistance training circles. So, get out your metronome or stopwatch and start being accountable for your actions.
Avoiding Explosive Exercise
The smoother and slower the repetition movement, the less momentum (mass x velocity) produced by the muscles, resulting in continuous muscular tension throughout the range of motion. Furthermore, slow speeds reduce the participatory effect of stored energy, or non-muscular torque, most prevalent when quickly reversing directions at the bottom of a movement for a quick turnaround.
Propelling or lifting a weight quickly produces less muscular tension throughout the ROM since the resistance is thrown upward and the muscles need not work optimally again until gravitational forces slow the weight down. Hence, within the zone where the weight is ?thrown,? muscles experience reduced tension.
Moreover, explosive actions produce a high level of potentially dangerous and injurious force at the commencement of a movement, due to a sudden jerk. High forces, caused by jerking a heavy barbell, are absorbed by the muscles and to a greater extent the tendons. The area most susceptible to soft tissue injury is the myotendinous junction, where the muscle attaches to the tendon. When you hear of bodybuilders tearing a muscle or tendon, often the tear occurred at that point. Considering the purpose of resistance training is to enhance functional ability, fast speed and acceleration must be eliminated from an exercise program to reduce the risk of injury.
Explosive movement also prematurely exhausts a muscle, resulting in a briefer tension time than if using the same resistance under slow conditions. This last point, as well as the previous point mentioned, are important to realize since strength and size increases are dependent on three aspects, whose quality and relationship must remain intact: 1. intensity (effort), 2. metabolic work (time), and 3. tension (strain).
These three elements help to determine the quantity of repetitions to perform for an optimum strength training stimulus.
In summation, keep explosive movement in the field; where it belongs and where it is specific to what you are attempting to achieve.
Brian D. Johnston is the President of the International Association of Resistance Trainers (I.A.R.T.), providing certification and education resources for personal trainers, coaches, and athletes. His website is www.ExerciseCertification.com, where you will find dozens of free articles on exercise and nutrition science, including several on proper coaching practices for athletes.
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