Welcome to rewind (Late) Friday. Sorry about the late entry, folks.

Along the vein of bike fit, to go with our lecture on onlinece.com this week, here is gentleman with right sided low back pain ONLY when ascending hills on his mountain bike. Can you figure out why?

*Stop, watch the video and think about it before we give you the answer… .

____________________________

This gentleman presented with low back pain, only on his mountain bike, only on long ascents.

He measures out with an 83 cm inseam which should put him on a 44 to 45.5 cm frame (measured via our method). His frame has a dropped top tube and measures 55 cm.

He has a knee bend angle of 20 degrees at bottom dead center. Knee is centered well over pedal axis.

His stem falls far in front of his line of sight with respect to his hub. Stem is a 100 mm stem with a 6 degree rise.

There is a 2” drop from the seat to the top of the handlebars.

He has an anatomically short Left leg (tibial)

Look at the tissue folds at the waist and amount of reach with each leg during the downstroke.

The frame, though he is a big dude (6’+), is too big and his stem is too long. He is stretched out too far over the top tube, causing him to have an even more rounded back (and less access to his glutes; glutes should rule the downstroke and abs the upstroke). This gets worse when he pushes back (on his seat) and settles in for a long uphill. Now throw in a leg length discrepancy and asymmetrical biomechanics.

Our recommendations: smaller frame (not going to happen) lower seat 5-7mm shorter stem (60-75mm) with greater than 15 degree rise lift in Left shoe

We ARE the Gait Guys, and we do bikes too!

What a difference a lift can make.

More from the pedal freaks….

Yes, we watch folks on bikes too. We look at foot and knee position, smoothness of strike, back position, as well as the spandex. Gait and biomechanics are everywhere and no one is safe from “the gait cam”.

Take a look at this gal and her pedal stroke. The first 9 second portion of the clip shows her pedal stroke with an increased medial migration of her L knee. Notice at about 4 seconds when she increases her cadence, it exaggerate the issue (see out post on that here). What sorts of things could cause that? A few causes are:

  •  Leg length discrepancy
  • Collapsed arch of L foot
  • Poor foot intrinsic strength of L foot
  • Poor eccentric contraction of L posterior gluteus medius complex
  • Weak lower abdominals L > R
  • Decreased ankle rocker of L foot
  • Cleat positioning on L shoe
  • Hip osteoarthritis
  • And the list goes on…

In this particular case, she had an anatomically short leg on the LEFT and weak foot intrinsics. Yes, we know, folks tend to pronate heavier on the LONGER leg side, but this is usually with running, not cycling. It tends (but not always) to be opposite with cycling. We believe this is due to the more rigid lasted cycling shoe and more of a “reach” with the foot on the short leg side.

In the second part of the clip, from 10 seconds to end, we place a 3mm lift on the left. THAT’S IT. Wow! What a difference! Still some oscillation of the knee at the top of her stroke (present on both sides, but more pronounced on the left), but much less. Note also that her body oscillation lessens as well and her stroke is smoother.

The Gait Guys. Not only are we watching how you walk, but also how you ride

Sometimes, you just need to add a little pressure….

Cyclists are no different than runners; often when the effort is increased (or the conditions reproduced), the compensation (or problem) comes out.

Take a good look at this video of a cyclist that presented with right sided knee pain (patello femoral) that begins at about mile 20, especially after a strong climb (approx 1000 feet of vertical over 6 miles through winding terrain).

The first 7 seconds of him are in the middle chain ring, basically “spinning” ; the last portion of the video are of him in a smaller (harder) gear with much greater effort.

Keep in mind, he has a bilateral forefoot varus, internal tibial torsion, L > R and a right anatomically short leg of approximately 5mm. His left cycling insole is posted with a 3mm forefoot valgus post and he has a 3mm sole lift in the right shoe.

Can you see as his effort is increased how he leans to the right at the top of his pedal stroke of the right foot and his right knee moves toward the center bar more on the downstroke? Go ahead, stop it a few time and step through it frame by frame.  The left knee moves inward toward the center bar during the power stroke from the forefoot valgus post.

So what did we do?

·      Worked on pedal stroke. We gave him drills for gluteal (max and medius) engagement on the down stroke (12 o’clock to 6 o’clock) to assist in controlling the excessive internal spin of the right leg. Simple palpation of the muscle that is supposed to be acting is a great start.

·      Did manual facilitation of the glutes and showed him how to do the same

·      Worked on abdominal engagement during the upstroke (the abs should initiate the movement from 6 o’clock to 12 o’clock)

·      Manually stimulated the external oblique’s

·      Placed a (temporary, hopefully) 5mm varus wedge in his right shoe to slow the internal spin of the right lower extremity

·      Taught him about the foot tripod and appropriate engagement of the long extensors; gave him the standing tripod and lift/spread/reach exercise (again to tame internal spin and maintain arch integrity)

Much of what you have been learning (for as long as you have been following us) can be applied not only to gait, but to whenever the foot contacts anything else.

The Gait Guys. Experts in human movement analysis and providing insight into biomechanical faults and their remediation.

All material copyright 2013 The Gait Guys/The Homunculus Group. Please use your integrity filter and ask before using our stuff. 

BIKE FIT: Case Study

Along the vein of bike fit, to go with Thursday and Friday’s posts last week, here is gentleman with right sided low back pain ONLY when ascending hills on his mountain bike. Can you figure out why?

*Stop, watch the video and think about it before we give you the answer… .

____________________________

This gentleman presented with low back pain, only on his mountain bike, only on long ascents.

He measures out with an 83 cm inseam which should put him on a 44 to 45.5 cm frame (measured via our method). His frame has a dropped top tube and measures 55 cm.

He has a knee bend angle of 20 degrees at bottom dead center. Knee is centered well over pedal axis.

His stem falls far in front of his line of sight with respect to his hub. Stem is a 100 mm stem with a 6 degree rise.

There is a 2” drop from the seat to the top of the handlebars.

He has an anatomically short Left leg (tibial)

Here is some additional video of him with a 3 mm lift in the left shoe. Look at the tissue folds at the waist and amount of reach with each leg during the downstroke in this one as well as the last. no changes were made to the seat height, fore/aft position of seat. or handlebars.

The frame, though he is a big dude (6’+), is too big and his stem is too long. He is stretched out too far over the top tube, causing him to have an even more rounded back (and less access to his glutes; glutes should rule the downstroke and abs the upstroke). This gets worse when he pushes back (on his seat) and settles in for a long uphill. Now throw in a leg length discrepancy and asymmetrical biomechanics.

Our recommendations:

  • smaller frame (not going to happen)
  • lower seat 5-7mm
  • shorter stem (60-75mm) with greater than 15 degree rise
  • lift in Left shoe


We ARE the Gait Guys, and we do bikes too!

Bike Fit Clinic Tonite

Drs Waerlop and Asthalter (Dr Ivo’s office) will be holding their annual bike fit clinic this evening from 6-7:30 at at Summit Chiropractic & Rehabilitation, PC in Dillon, Colorado. frame sizing, seat height, fore and aft positioning, and handlebar height will be discussed, with common dysfunctions resulting from improper fit.

The event is usually a sell out, and we expect nothing less this year. Highlights to follow on the blog!

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A brief note on internal hip rotation from a cyclists perspective.

Today is Stage 14 in the Tour De France. We are big fans and we treat tons of Triathletes. So, it seemed perfect to do a little bike fit and mechanics today.

On the subject of cyclists, we have noted many have these 3 anatomical traits: femoral retoversion (see recent blog posts this week), tibial varum, forefoot varus. If you look at these closely, they all tend to supinate the foot foot more and make it a better lever. These folks are way better cyclists than runners.

With a FF varus, they often compensate on the down stroke to make the foot flat on the pedal (to use the 1st MTP); if they are retroverted, they have limited hip internal rotation to begin with and now you are asking them to internally rotate more, which leads to hip pain and at times, labral injuries.

Look at the attached clip, R leg; note how it comes closer to the center bar and the position of the knee; also look at the forefoot.

Yup…The Gait Guys…We do bikes too!