Workout question

January 26, 2015 12:35 PM

[exercise filter] Please explain to me how the relationship between sets and reps works.

To elaborate on the vagueness above, I'm doing a bodyweight exercise routine. The program gives me a goal of two sets of fifteen reps for pull ups. I have hit a plateau trying to reach this goal. One piece of advice I saw online is to try performing an equivalent number of reps over an increased number of sets. E.g. spreading (15 reps x 2 sets = 30 reps out over 5 reps x 6 sets).

I notice that if I attempt two sets of 15 reps, I feel destroyed afterwards. But if I do 6 sets of 5 reps each, I feel like I can easily keep going. Given that the same amount of work is being done, why does the one routine affect my body more than the other? Physiologically speaking, am I doing anything different to my body? How do the two routines affect the body differently in terms of stimulating strength / endurance / etc?

posted by prunes to Health & Fitness (8 answers total)

You need to factor in cardio here. You may be doing the same amount of work (i.e. weight lifted X times), but with more sets / fewer reps, you're giving your heart little rest periods. That's why you don't feel wrecked.

People will tell you all sorts of things about what scheme is "best," so be wary, do what works for you.
posted by Cool Papa Bell at 12:44 PM on January 26, 2015

Chemicals. Don't ask me which ones, IANAP(ersonal)T(rainer), but the basic idea is that as you progress through a set, you deplete certain chemicals in your muscles that are required to keep... muscling. So the longer the set goes on, the less fuel you have to continue. Eventually if you keep going, you run out of fuel and fall to the mat, gasping and crying.

But if you break up the exercise into smaller chunks, your body has time to replenish those chemicals between sets. It doesn't take a huge amount of time if you're in decent shape. The longer you rest between sets the closer you get to a full tank for your muscles, so the more sets you can do.

How long you should go between sets to get maximum benefit varies depending on who you ask. Some say you only need thirty to sixty seconds. Personally, I prefer at least a day. (A day with a pizza in it, if I can get one.)
posted by kythuen at 12:58 PM on January 26, 2015 [3 favorites]

The simple way people typically think of sets and reps is that low reps is high weight muscle building activity. High reps is lower weight muscle stamina building.

If you can't complete the pullups lots of workouts suggest cheating on your remaining 'ups' and doing slow controlled 'downs'.
posted by srboisvert at 1:00 PM on January 26, 2015 [1 favorite]

Isn't it all resting time? Hanging from a bar requires some exertion too, definitely more than resting between sets. If you told me to do 1 set of 30 pullups, I wouldn't be able to do it, but if you said I can spread the 30 pullups over the entire day and do in sets of 1 every half hour, then of course I could do it.
posted by pravit at 2:50 PM on January 26, 2015

Response by poster: But why would my muscles, later in the day, feel more deteriorated in scenario A than scenario B? If Kyuthen's theory is true and applicable here, I'd love additional information on it.
posted by prunes at 2:54 PM on January 26, 2015

But why would my muscles, later in the day, feel more deteriorated in scenario A than scenario B?

Why wouldn't they? Muscles recover from stress/work given time. Taken to extremes this is obvious: If you did 5 pullups a day over 6 days then when you were done you wouldn't expect to feel as tired as if you did 30 all at once, even though it's the same amount of work. If you did 5 pullups an hour, same thing.

You already know that muscles recover over time -- I think that just starts happening earlier than you think: A little bit of rest just allows the muscles to recover a little. So for some made-up numbers, if doing 5 pullups causes 5 units of tiredness, and the rest period between sets is enough time to allow your muscles to recover 1 unit of tiredness, then 15x2 would get you to 29 units of tiredness(15-1+15), but 6x5 would only peak at 25 units of tiredness (5-1+5-1+5-1+5-1+5-1+5), which would then be easier to recover from throughout the day.

Obviously it's not that clean, but the theory works.
posted by brainmouse at 3:04 PM on January 26, 2015 [1 favorite]

Best answer: This is actually a topic of active research. Nobody knows what exactly causes muscle soreness.

There's a very sensible but incorrect theory that work which outpaces aerobic metabolism causes muscles to switch down to lactic acid fermentation to make up the shortfall, and soreness resulted from this lactic acid accumulation. This was pretty definitely disproved by an experiment where half the people ran uphill, half the people ran downhill, and only the downhill runners reported soreness despite both groups testing at equal lactic acid levels.

Note, though, that it's almost certainly not true that you're doing an equal amount of work in your long sets vs your short sets. As you fatigue, your reps become slower. Unlike ideal machines in physics, your muscles burn energy just straining to hold still.
posted by d. z. wang at 3:24 PM on January 26, 2015 [1 favorite]

Get thee reading on Strength & Science for serious analyses of this
posted by lalochezia at 5:07 PM on January 26, 2015