clipins or flats - the science behind it

rickbst170

Lol, yeah. Long time since I applied myself to any mechanical engineering. It's not so much the relationship between energy, power and speed I'm looking at (a downstoke and an upstroke cover the same distance so at the same speed you get the same work done. In essence, they are equally as efficient). It's more to do with the body's energy consumption to do that upstroke vs downstroke.

Just read this abstract but haven't read the paper. Stolen from mtbr forum. My interpretation of it is that there is less efficiency clipped in vs not clipped in amongst pro and inexperienced riders. More effective (got the job done) but less efficient.

One hit from the PubMed/Medline search database on search terms "clipless pedal efficiency," with a few related studies cited following the main article abstract:

Int J Sports Med. 2008 Oct;29(10):817-22. Epub 2008 Apr 17.

Effects of pedal type and pull-up action during cycling.

Mornieux G, Stapelfeldt B, Gollhofer A, Belli A.

Institut für Sport und Sportwissenschaft, Universität Freiburg, Freiburg,
Germany. guillaume.mornieux@sport.uni-freiburg.de

The aim of this study was to determine the influence of different shoe-pedal
interfaces and of an active pulling-up action during the upstroke phase on the
pedalling technique. Eight elite cyclists (C) and seven non-cyclists (NC)
performed three different bouts at 90 rev . min (-1) and 60 % of their maximal
aerobic power. They pedalled with single pedals (PED), with clipless pedals
(CLIP) and with a pedal force feedback (CLIPFBACK) where subjects were asked to
pull up on the pedal during the upstroke. There was no significant difference for
pedalling effectiveness, net mechanical efficiency (NE) and muscular activity
between PED and CLIP. When compared to CLIP, CLIPFBACK resulted in a significant
increase in pedalling effectiveness during upstroke (86 % for C and 57 % NC,
respectively), as well as higher biceps femoris and tibialis anterior muscle
activity (p < 0.001). However, NE was significantly reduced (p < 0.008) with 9 %
and 3.3 % reduction for C and NC, respectively. Consequently, shoe-pedal
interface (PED vs. CLIP) did not significantly influence cycling technique during
submaximal exercise. However, an active pulling-up action on the pedal during
upstroke increased the pedalling effectiveness, while reducing net mechanical
efficiency.

PMID: 18418807 [PubMed - indexed for MEDLINE]

supersonic

Pedaling effectiveness refers to evenness of torque transfer, I believe.

cooldad

When things get too difficult and my brain starts hurting, I like to ride my bike.

rickbst170

Ok, just scan read the paper and I think it says there was no real difference between clipped in and not clipped in, because you get more power clipped in but it costs more energy so you tire faster. But it also says that this was only at less than 60% of people's ability and when flat out (sprinting etc) there is likely to be a big difference, clipped in being better.

I think. So clipins win. I think.

welshkev

I like to ride my bike and not care that I may get an extra 3.3% more efficiency from being clipped in and turning my pedals 0.2% more often on a Tuesday at exactly 4.27pm

mmacavity

http://www.pinkbike.com/news/Shoe-Pedal ... -2012.html

njee20

Your fundamental misunderstanding seems to be that with flat pedals you push down, whilst with clips you pull up. If you ride clipless in the same way as flats then they're identical, there's no inherent reason you have to pull up with clipless. As you say, it's a far less efficient motion than pushing down, one just doesn't have the strength to make a meaningful difference.

Angus Young

welshkev wrote:

I like to ride my bike and not care that I may get an extra 3.3% more efficiency from being clipped in and turning my pedals 0.2% more often on a Tuesday at exactly 4.27pm

Well, it only took 5 pages to get to the correct answer.

ilovedirt

It's entirely obvious that clips are more efficient than flats. Moving your feet around on the pedals = energy lost. Clipped in means 1 more point where you're not wasting energy on unnecessary movement. Whether or not it's noticable or not is another question, I just find pedalling more pleasant when i'm clipped in.

bladeone

thought I'd give flats a go and try and relearn and get shut of some of bad habits I've think I've got.
OTB today due to a pedal strike ( stump ) so thinking about scraping the flats idea lol
I found it difficult, feet not always been in same position and worrying about my feet losing the pedals , gonna try again but at present not much confidence in them

BigAl

Peat wrote:

I felt the benefit immediately on XC and climbing. I also find that riding clipped in encourages me to 'pedal through' the tricky/slippery stuff rather than wimp out/stop and put a foot down as a did before. The main thing that stopped me doing it sooner was fear of silly falls. So far, it has never come to pass, I have always managed to unclip somehow

I hear what you're saying and get it - but it can work the other way too

My background as a roadie meant that when I started on an MTB I went immediately to SPDs. Trouble was, when I got too the tricky/slippery stuff I'd worry about whether I could unclip. Never really happened that I couldn't - but the thought was still there. I now ride flats and, because I know I can dab if I need to, I tend to ride through the tricky/slippery stuff which I didn't on SPDs.

Each to their own (and I do still use SPDs for some rides). I've also found flats to be much more grippy than I would ever have thought.

Berkshire Rich

bladeone wrote:

thought I'd give flats a go and try and relearn and get shut of some of bad habits I've think I've got.
OTB today due to a pedal strike ( stump ) so thinking about scraping the flats idea lol
I found it difficult, feet not always been in same position and worrying about my feet losing the pedals , gonna try again but at present not much confidence in them

Might need better pedals? Just got superstar nano techs and they are excellent, with brilliant grip.

bladeone

Berkshire Rich wrote:

bladeone wrote:

thought I'd give flats a go and try and relearn and get shut of some of bad habits I've think I've got.
OTB today due to a pedal strike ( stump ) so thinking about scraping the flats idea lol
I found it difficult, feet not always been in same position and worrying about my feet losing the pedals , gonna try again but at present not much confidence in them

Might need better pedals? Just got superstar nano techs and they are excellent, with brilliant grip.

It was more to do with technique and ground clearance being use to spd, but how would better pelals stop a pedal strike?

And they are the same superstar pedal as you mention.

Berkshire Rich

Was replying to your point about feet moving around on pedals / worry that you may not stay connected. Better pedals would help here but not necessarily address the ground clearance issue, if there is one

The secret rider

A "funny" the happened this weekend that made me think of this thread.... riding a local trail centre mate of mine was in front of me... We are not hanging about ... pedal stroke down pedal / foot gets snagged on a low tree stump bike and him stop instantlly he does a flip mid air still clipped in mid air almost upside down manages to Un clip and the bike goes flying he lands on his bum. Poor chap but made me think he swears by SPDs and although he could not unclip instantlly he was ok ... Probably no worse of than if he had flats on

rockmonkeysc

If they're set up right they alway unclip in a crash.
I missed the landing on a big hip jump yesterday and launched in to the scenery. My feet unclipped instantly.
My main problem was a big jump in strong winds, my own fault.