My wussy workout made me think

As you may know from Jess's bloggo-- we've been on a New Year's workout kick that's still ticking as of March 4th (As my dad has joked-- March 4th: the one date that's also a command. March Forth!)

So I woke up sore this morning from my workout yesterday and thought that's weird-- why am I sore ALREADY? I've been getting sore on the second day following my workout. I did a leg muscle workout (ugh!) yesterday, but really didn't work that hard-- lots of reps at low weight. I wasn't totally goofing around-- still had a sweat ring, but I wasn't killing myself on any one workout. I didn't give my 110% by any means.

This quick-onset of soreness after my low intensity workout made me think-- do intense muscle training exercises give you delayed onset soreness, while cardio-like workouts cause more immediate soreness?

Kind of. After googling around a bit, I first was disappointed at the confusion and lack of a clear answer. But there seems to be a standing theory that, "the type of exercise – intensity, duration or type of contraction – influences time course. Most researchers have started from the observation that soreness is most severe after eccentric contractions [14]," Okay, we're on to something... but what the hell are eccentric contractions? You all may already know, but this was new to me: concentric contractions are 'normal' muscle contraction. But eccentric contraction is the work of a muscle as it resists opposing force to decelerate the movement. Like if you're doing pullups-- after you get your chin above the bar, rather then just falling, you resist your weight/gravity's force by slowly lowering yourself to starting position.... That's supposedly amazing for muscle growth and seems to be heavily correlated with delay-onset muscle soreness. And why you overhear trainers saying-- Up...And now down--slowly! Because you're basically forcing your muscle to work just as hard as going up but mechanically the muscle is creating its cross-links in the opposite direction.

Yesterday at the gym, my muscles still got crazy exhausted, even though I was doing low weight. I didn't consider that I was skipping half my workout by making the 'And Down' part way too easy.

Conclusion: because I was a wuss yesterday at the gym, I'm already sore today. booo. I'm a procrastinator, so this doesn't sit well with me.
EDIT: But runners get Delayed-Onset Muscle Soreness... which seems more similar to low-weight, more reps... hmmmmm.....

Keep in mind, my "research" consisted of a 15 minute internet search at 6:30am.