Group Power Classes

Question:

Has anyone evaluated the group power classes that seem to be very popular right now? Obviously, it's endurance exercise since you challenge a single muscle group for five minutes. Is it a good addition to a program that includes other strength and power components?

Answer:

I've recently reviewed several popular resistance-orientated group exercise programs and formed the following conclusions (to read more on my research, please click here). All classes that I evaluated did have a strong muscular endurance profile in a two dimensional sense. However, for novices, there are marked gains in both absolute and relative strength (as can be expected from any long term resistance training program) as the body improves neurological parameters (synergy, summation, etc), and the muscular system adapts. With several programs including relative strength exercises like lunges, push ups, sit-ups, etc, relative strength improves and, as repetition ability increases, the gains translate into relative strength-endurance (i.e., endurance moving your own body weight).

Any power increases would come from the increase in strength (power = speed + strength). However, in reality, the power gains would be very minimal (if at all) because the speed of movement is too slow and the use of weights teach an “end range deceleration” (breaking) pattern, meaning they teach the muscles to decelerate the weight towards the end of the range to protect the joints as the load is not going to be released.

In a nutshell, beginners and ultra high repetition endurance athletes tend to increase their strength profiles. Strength athletes and everyday resistance trainers tend to increase lactic (H ion) tolerance and endurance.

Heart rate data found that during leg and back tracks in particular, heart rates reached as high as 180 beats per minute in some members (these members had a long history of these classes and knew the music tracks and how to maximize their loads) with other members sitting comfortably on 120 to 160 beats per minute or around 60 to 70 percent of Predicted Maximal Heart Rate (utilizing the Karvonen formula). I must admit to never conducting a pre-program/post long period of attendance cardiovascular assessment. The resultant VO₂ scores may have been interesting.

Exercise Order

Most classes from various programs I observed did breach recommended exercise program order by doing the following:

• Most complex/neurologically demanding exercises performed first - Several programs had demanding exercise like lunging and Olympic orientated lifts later in the program. As such, the participants’ techniques were reduced. A major irony is the instructors tried to correct the technique, which the participants could not physically correct due to fatigue. For example, trying to enforce bending the knees with a clean and press when their legs were fatigued, the participants tended to lock them out just to stand up without having their legs shake from fatigue. Another example is enforcing spinal posture in a lunge when the lower back has been fatigued from earlier back exercises. However, some programs do utilize a non weight bearing track between exercises of this nature to allow the lower limbs some recovery.
• Compound before isolation - Again, almost all programs breached these guidelines. Performing activities like biceps curls and triceps extensions before exercises like push ups, upright row and shoulder press. Thus, the pre-fatigued minor muscle groups become the limiting factor in the exercises.

Good Programming Considerations

Many of the programs also did not follow the general considerations for a good resistance orientated program such as:

• Proportionate Loading - For the programs that utilize a single track per body part, there is almost always an over loading of the minor muscle groups. Consider a five minute chest track, which predominantly utilizes chest, anterior shoulder (both for horizontal shoulder extension/adduction) and triceps (elbow extension) as prime movers. Then consider adding another five minutes on an isolated exercise (elbow extension) for the triceps. At the end of the session, the chest has had around five minutes training stimulation. The triceps, a markedly smaller muscle, has had at least the same amount of stimulation as the chest and often more (when the work done performing elbow extension for the chest and shoulder exercises are included). Many novices to a certain program are even warned about the fact that they will not be able to bend and straighten their arms for the next few days following the class due to brachialis fatigue, a relatively small (albeit important) muscle that crosses the elbow joint. This warning brings with it no surprise. I counted the repetitions during one class and found the major muscles of the upper back were involved in 46 isotonic repetitions (approximately two of the four minutes of the track), which all included the biceps to flex the elbow. The class then performed 84 biceps curls (approximately four minutes) during the biceps track. The biceps also performed 24 repetitions for an upright row.
• Recovery - On the whole, the requirement to allow at least 48 hours recovery between sessions was adhered to with only a few participants breaking these guidelines.

With a general review out of the way, we can answer your question of whether group power classes are a good addition to a program that includes other strength and power components. As with every component of a training program, my first question is always “why?” Why do you want to include it into other strength/power components? It is the “why” that will determine whether it is or is not suitable for inclusion. Once you have decided why, then read on and the information below should help you make your decision.

Most marketed group resistance training classes will potentially impact negatively on an intermediate athlete’s strength and power development for the following reasons:

• Power and strength require high neural drive for development (i.e., motor unit summation and wave summation) and therefore require at least three to six minutes of rest in between sets in order to allow neural recovery prior to the next set.
• The metabolic profile for maximal strength/explosive power is the ATP–PCR system. This system is limited and lasts for a very short period (up to 15 seconds, depending on sources) and requires around 30 seconds for 50 percent recovery and up to three minutes for a maximal recovery. This factor and the one above explain why strength/power athletes require three to six minutes of rest between sets. If there is no change to your current strength/power training, the additional high duration of stimulus of these programs will impact on recovery.
• These programs use slow repetitions (compared to power) to ensure safe lifting, which is beneficial to the average person training in the gym but of limited value to a power athlete. Furthermore, you only generally develop strength/power at the speed you train and slower (the Force – Velocity curve), so if you train slow, you get stronger at slower speeds only.
• The exercise volumes and order are not optimal and will potentially overload minor muscle groups.
• The exercises are generally compound to isolation in nature and do not use high kinetic link exercises. Profiles like segmental force velocity are therefore hindered (think of the difference between a bunch of words on paper versus a bunch of words structured into a readable sentence).

This is not to say there is no room for some of these classes in a program that includes other strength and power components. The classes can be used as a form of recovery (as part of a periodized program) from high neural drive training (very heavy 1 to 8 RM lifting). Many athletes find the classes enjoyable during periods of low motivation with pumping music and motivating instructors. 

Some other points to consider before including group power classes into a program.

• One instructor with up to 60+ participants equals extremely limited individual coaching (especially when the instructor is too focused on the choreography and the music).
• While training to music can be motivating, for those who don’t like the music choices, listening to your own music is not an option.
• Pre-choreography means always knowing the format and, together with good instructors (who give you an idea on the intensity and volume of the track), allows you to push harder than you normally would.
• Controlled speed of movement means less use of momentum and more time under tension.
• It’s a great way of introducing basic resistance training to those who feel uncomfortable in a resistance training room (technique classes with small numbers).

So in essence, if focusing on strength/power for a dedicated strength and power athlete, I would only include these class types as part of an active recovery from higher intensity (neural drive) training. For the recreational strength/power trainer, these programs can be used as part of the high volume phase of training when cycling away from high intensity training.