Flip Flops not so bad? We still think they suck and here's why...

We have talked about the dangers of open back shoes (Including flip-flops)  and loss of ankle rocker as well as changes in forefoot rocker and great toe dorsiflexion on our blog many times.

The findings of this study, with slower cadence and shortened stance are not surprising (especially since you need to fire your long flexors to keep them on!) nor are ankle joint kinematics (flip flops have no heel counter and are not torsionally rigid, so naturally there would be increseased subtalar motion), however we really question the interpretation.

 "Many have long suspected the answer, but a new study would appear to resolve the question: Are flip flops really that bad for your feet? According to Chen and colleagues from the Department of Biomedical Engineering at The Hong Kong Polytechnic University, flip flops are most likely no better than barefoot when it comes to lower-limb co-contraction and joint contact force in the ankle. The authors had hypothesized that the popular rubber footwear would increase co-contraction of the muscles between the knee and ankle joints in what they thought was a compensatory mechanism for the unstable foot–sole interface and would affect gait kinematics and kinetics.

In the study, the researchers had 10 healthy males perform 6 walking trials under 3 conditions: barefoot, sports shoes, and thong-type flip flops. Participants, who reported they were not “regular flip flop wearers,” were fitted with numerous markers that were monitored while they walked on a 10-meter pathway. The study looked at several muscle pairings that stabilize the knee, ankle, and subtalar joints, including vastus lateralis and gastrocnemius medialis; vastus lateralis and biceps femoris; and peroneus longus and tibialis anterior.

In pairwise comparisons, the walking velocity of flip flops was lower than that of sports shoes (p<0.01) but comparable to barefoot (p>0.05), findings that were consistent with the published literature. Although not significant, the minimalist footwear produced a slower cadence and shortened stance phase in walking trials compared to the other 2 types of footwear. Joint kinematics differed significantly in the ankle joint (F[2,18]=6.73, P<.05) and subtalar joint (F[2,18]=4.45; P<.05); Furthermore, ankle and subtalar range of motion was higher for flip flops than for sports shoes. However, co-contraction was not enhanced. The authors propose that walking speed does not need to be consistent for real-world activities and the slower speed could be a natural approach to avoid injury.

The authors conclude that the slowed walking speed of flip flop users could account for the comparable joint biomechanics between flip flop use and barefoot. They note, however, that, for injury prevention, the closed-toe design of the sports shoe would provide better support for joint motion and loading compared to the other 2 options."

Source:

Chen TL, Wong DW, Xu Z, Tan Q, Wang Y, Luximon A, Zhang M. Lower limb muscle co-contraction and joint loading of flip-flops walking in male wearers. PLoS One. 2018;13(3):e0193653."

image and article source: http://lermagazine.com/issues/may/flip-flops-bare-feet-or-sports-shoes-which-are-best-and-which-are-worst

Gait help: How and where to carry a cane, and why.

Test Question from this photo:

This lady on the right is using her cane and purse correctly IF, she has a degenerative hip on the RIGHT or LEFT ?

Answer: LEFT hip

Why, because the cane in the right hand pressing down creates a ground reactive force back up through the cane, helping to tip her torso to the left, the passive cane-generated lean in effect reduces the left gluteus medius compressive load across a painful degenerative hip. Result, less painful gait.

But, she is also brilliant to use the purse in the left hand, to effectively PULL her torso over the left hip (again, limiting g.medius joint compressive forces through more passive means).
End result, less compressive pain loading across a degenerative joint.
*IF we were her daughter we would help by putting a 10 pound brick in the purse, just to help of course.

IF she however has a painful degenerative right hip, school her.

Gait changes with your weight change?

Does a sudden gain in one's weight change their gait? Well, in this study, another form of weight change sure seemed to change the gait of these ladies.

The primary aim of this study was investigate the changes in gait and postural control as factors of stability during walking. Gait and posture of thirty-five (35) pregnant women and the results indicated that there were significant associations noted between:
- step width,
- lateral trunk lean, and
- medio-lateral deviations in center of gravity and center of pressure.

They found among other things, that the lateral trunk lean is the primary factor women use in pregnancy to keep the center of gravity closer to the base of support. "Postural changes and those in gait kinematics were largely affected by the relative mass gain, rather than the absolute mass. Considering the importance of relative mass gain, more attention during healthy pregnancy should be given to monitoring the timing of onset of musculoskeletal changes, and design of antenatal exercise programs targeting core strength and pelvic stability."

We concur, we can see this lateral trunk lean in clients all the time who have challenges in hip-pelvis-core stability in the frontal plane. Stability work, primarily of the hips is critical for these clients. This work often serves pregnancy clients well, it helps to fend off some of the late term pelvis and low back problems as the frontal mass develops.

If this is new information for you, you should head over to our website/blog and start your learning process with the fundamentals of the "cross over gait" because that in essence is what we are talking about here.

https://www.ncbi.nlm.nih.gov/pubmed/29254847

Hum Mov Sci. 2017 Dec 15. pii: S0167-9457(17)30750-9. doi: 10.1016/j.humov.2017.12.011. [Epub ahead of print]  Changes in gait and posture as factors of dynamic stability during walking in pregnancy.  Krkeljas Z1.

You cannot make gait corrections based on "visual assessment and oral instructions"

our Christmas #facepalm of the day

These clients changed their gait habits with visual and verbal cues. We can only hope that for the rest of their lives they have this software and someone walking beside them to give them the visual and verbal cues for the rest of their lives so that they can continue to walk "normally" again, which is likely a compensation to their compensatory deficits (instead of earning the changes through championing their way through their deficits.)

Uggg. We have said this over and over again, and will say it again here.
You cannot make gait corrections based on "visual assessment and oral instructions" (as this paper mentions). This is borderline foolish. A person's gait has changed for a reason, they did not do it consciously. Thus, they should not lean towards a simple conscious correction. Their body made the adaptive changes one can see on gait evaluation because of an adaptive deficit, weakness, pain, compensatory motor strategy etc. There is a reason their gait has changed. Thus, the fix must come from addressing these causes, not merely from a visual cue or a verbal instruction. This is foolish. This is what is wrong with the gait assessment world. This is why you cannot and should not give corrective exercises from a gait analysis, not until you examine your client clinically for deficits, weakness, faulty motor patterns, sensory deficits, etc. This is just not prudent work without the clinical evaluation, hands on stuff, smart stuff.
These clients changed their gait habits with visual and verbal cues. We can only hope that for the rest of their lives they have this software and someone near by to give them the visual and verbal cues for the rest of their lives so that they can walk normally again (instead of earning the changes through championing their way through their deficits.)
#facepalm of the day

http://www.jbiomech.com/article/S0021-9290(17)30570-5/abstract

A gait retraining system using augmented-reality to modify footprint parameters: Effects on lower-limb sagittal-plane kinematics . Sami Bennour, Baptiste Ulrich, Thomas Legrand, Brigitte M. Jolles, Julien Favre

Imaging things can make them better.

Imagining can make things better.

Visualization is a key in most sports and activities if one wants to improve their skill and performance. Gait retraining through visualization should thus work as well. This study which has yet to be executed, hypothesizes that we should be able to change and improve our gait through visualization of changes. Motor imagery, envisioning motor actions without actual execution, has been used to improve gait in Parkinson's disease and post-stroke. In this study subjects will be asked to specifically imagine walking, imagine talking and imagine walking while talking. It will be interesting to see what they discover, but we suspect that this should be like improving any other motor task, that visualization improves the task. Learning occurs on several levels. One should also consider not only asking clients to do their prescribed corrective exercise homework and movements, but also visualize them even when actual physical execution is not feasible.

Neurodegener Dis Manag. 2017 Nov 22. doi: 10.2217/nmt-2017-0024. [Epub ahead of print]
Motor imagery of walking and walking while talking: a pilot randomized-controlled trial protocol for older adults. Blumen HM1, Verghese J1.

Cannabis users walk differently.

We all have experienced or viewed the alcohol impaired gait at some point in our lives, the sloppy malcoordinated limb and torso movements. There are some classic observable characteristics there that many of us are familiar with. But what about cannabis gait ?

"The research from the University of South Australia, published in the journal Drug and Alcohol Dependence, found those who smoke cannabis tend to move their shoulders less and elbows more as they walk. The pilot study also found marijuana users swing their knees more quickly during walking. The differences in gait were small and found in people who smoked a light or moderate amount of cannabis. Some changes were so small it was impossible for a specialist to detect."

However, the thing we found interesting was the papers final question, as to whether the subtle gait changes over a longer period of time would increase or become more apparent.

*We have seen this variation in arm swing gait many times before. We have discussed numerous times that when there is a reduction in the normal shoulder and pelvic "girdle" counter rotations, the normal antiphasic gait that presents us with the clearly obvious opposite arm-leg swings, we lose the ability to tap into these oscillations that afford us this free arm and leg swing. So, when these girdle rotations are reduced, the limb movement has to come from further down into the limb, from elbow movement, a sort of casting the lower arm forward from biceps and triceps activity and from a kicking forward of the lower leg from quadriceps activity instead of hip flexion-extension activity.

Gait affects everything, and everything seems to affect our gait.

https://www.9news.com.au/national/2017/09/01/15/25/marijuana-users-walk-differently-australian-study-claims

Party over the Weekend?

So, the more you drink, the more you impair the CNS. The more you impair the CNS, the more dependent you become on peripheral mechanisms. A good reason to keep your vestibular system (alcohol changes the specific gravity of the endolymph), your visual system (long term use affects the option nerve directly and can cause involuntary saccades) and proprioceptive systems including the cutaneous mechanoreceptors (because you are relying on them more) intact. Watch what and how much you drink...

"Standing postural stability relies on input from visual, vestibular, proprioceptive and mechanoreceptive sensors. When the information from any of these sensors is unavailable or disrupted, the central nervous system maintains postural stability by relying more on the contribution from the reliable sensors, termed sensory re-weighting. Alcohol intoxication is known to affect the integrity of the vestibular and visual systems. The aim was to assess how mechanoreceptive sensory information contributed to postural stability at 0.00% (i.e. sober), 0.06% and 0.10% blood alcohol concentration (BAC) in 25 healthy subjects (mean age 25.1 years). The subjects were assessed with eyes closed and eyes open under quiet standing and while standing was perturbed by repeated, random-length, vibratory stimulation of the calf muscles. Plantar cutaneous mechanoreceptive sensation was assessed for both receptor types: slowly adapting (tactile sensitivity) and rapidly adapting (vibration perception). The correlation between recorded torque variance and the sensation from both mechanoreceptor types was calculated. The recorded stability during alcohol intoxication was significantly influenced by both the tactile sensation and vibration perception of the subjects. Moreover, the study revealed a fluctuating association between the subjects' vibration perception and torque variance during balance perturbations, which was significantly influenced by the level of alcohol intoxication, vision and adaptation. Hence, one's ability to handle balance perturbations under the influence of alcohol is strongly dependent on accurate mechanoreceptive sensation and efficient sensory re-weighting. 

Modig F, Patel M, Magnusson M, Fransson PA.Study II: mechanoreceptive sensation is of increased importance for human postural control under alcohol intoxication. Gait Posture. 2012 Mar;35(3):419-27. doi: 10.1016/j.gaitpost.2011.11.001. Epub 2011 Dec 27.
weighting.

Gait changes on a treadmill

Something to ponder on those days when getting outside it just impossible because of weather.
Athletes might respond to fatigue differently when running on a treadmill compared with overground conditions, where pace is typically more variable.
“Before halfway, step length increased and cadence decreased, whereas during the latter stages, there were significant decreases in impulse and maximum force. Contact time decreased and flight time increased continually, but otherwise most gait variables did not change. The changes in contact and flight times suggested that athletes altered their gait so that more time was spent airborne to allow the treadmill to pass under them. In general, however, the runners maintained their techniques throughout the run. ”

http://www.ncbi.nlm.nih.gov/m/pubmed/23860291/

Human Gait Changes following mastectomy. Taking Angelina Jolie's news and putting it into gait context.

The Gait Guys are on the case looking at the effects of gait changes following mastectomy just a day after the news of Angelina Jolie’s double mastectomy.

Research has confirmed that following a mastectomy there are limitations in the efficiency of the upper limb and even changes in the posture of the torso. (1,2,3)

Following mastectomy, whether unilateral or bilateral, restorative measures are necessary. From a biomechanical perspective, obviously depending on breast size, removing a considerable mass of tissue is going to change the symmetry of the torso particularly if we are dealing with a unilateral mastectomy.  Not only is it going to change symmetry from a static postural perspective but it will change dynamic postural control, mobility and stability as well as dynamic spinal kinematics.  The literature has even shown that post-mastectomy clients display changes in spatiotemporal gait parameter such as step length and gait velocity.

Breast tissue moves. It oscillates a various cycles depending on speed of walking or running.  There is a rhythmic cycle that eventually sets up during walking and running and the cycle is intimately and ultimately tied to arm swing.  Thus, it would make sense that removing a sizable mass of tissue, particularly when done unilaterally, will change the tissue and joint rhythmicity. And if you have been here with The Gait Guys for more than a year you will know that impairing an arm swing will show altered biomechanics in the opposite lower limb (and furthermore, if you alter one lower limb, you begin a process of altering the biomechanical function and rhythmicity of the opposite leg as well.)  Here are 2 links for more on these topics, Arm Swing: Part 1 and Arm Swing: Part 2, When Phase is Lost. Plus here from our blog search archives, everything we have talked about on Arm Swing.

Arm swing impairment is a real issue and it is one that is typically far overlooked and misrepresented. We are currently working on several other blog posts for near future release including walking with a handbag/briefcase, walking with a shoulder bag, walking and running with an ipod or water bottle in one hand and even spinal symmetry changes from scoliosis that can either consciously or unconsciously alter arm swing and thus global body kinematics.  (We have also noted changes in opposite leg function secondary to a frozen shoulder (adhesive capsulitis) and we have that blog article in the works as well.)  The bottom line is that because of the neurologically embedded crossed extensor reflex and cross crawl response that permeates all human locomotion, anything that changes one of the limbs, whether it be a direct limb issue or something to do with the stabilization of the limb (as in this case the breast/chest wall), can and very likely will impair and change locomotion and motor pattern choices and programming.

Obviously the degree to which intervention is taken depends on the amount and location of breast tissue removed and intervention will be determined by physical placement of the prosthesis (whether it be external or internal) as well as the prosthesis weight, shape and possibly several other independent factors such as comparative support to the chest wall in comparison to the opposite breast. (In another future blog post we will address other methods of intervention such as latissimus dorsi relocation to reform the breast mass. This deserves a blog article all on its own because taking away a major shoulder, scapular and spinal stabilizer and prime mover has never made sense to us clinically or biomechanically.)

In Hojan’s study (below) they found significant differences in the gait parameters in the younger age groups with and without breast prosthesis however there appeared to be no significant differences in the women of the older study group.  However, it appeared that their study did not take into account all of the intimate issues we talk about in gait here on The Gait Guys blog. None the less, in the younger and likely more active study group, the use of a breast prosthesis brought the gait parameters closer to the healthy control group, as we suspected. 

Bottom line, every external and internal parameter that changes affects the human organism and thus affects their gait.

Again, here are those links to our other blog writings on arm swing that are paramount to understanding what we are discussing here today.

Arm Swing Part 1: The Basics    http://thegaitguys.tumblr.com/post/13869907052/arm-swing-in-gait-and-running-part-1-there-is

Arm Swing Part 2: When Phase is Lost    http://thegaitguys.tumblr.com/post/13920283712/arm-swing-part-2-when-phase-is-lost

From our blog search   http://thegaitguys.tumblr.com/search/arm+swing

Shawn and Ivo, The Gait Guys

References:
1.Blomqvist L, Stark B, Engler N, et al. Evaluation of arm and shoulder mobility and strength after modified radical mastectomy and radiother- apy. Acta Oncol. 2004;43(3):280Y283.

2. Rostkowska E, Bak M, Samborski W. Body posture in women after mastectomy and its changes as a result of rehabilitation. Adv Med Sci. 2006;51:287Y297.

3. Crosbie J, Kilbreath SL, Dylke E, et al. Effects of mastectomy on shoulder and spinal kinematics during bilateral upper-limb movement. Phys Ther. 2010;90(5):679Y692.

4. Hojan K, Manikowska F, Molinska-Glura M, Chen PJ, Jozwiak M. Cancer Nurs. 2013 Apr 29. [Epub ahead of print] The Impact of an External Breast Prosthesis on the Gait Parameters of Women After Mastectomy.