my sanity escape! :)

9.01km, 60 mins!
hills L3

my sanity escape! :)
did the last 1/3 changing my footstrike from my usual heel strike to the forefoot strike.

one of my clinicalgrp mates comment tt my walking gait was weird with inward torsion of my left ankle. i have injured my lateral ankle ligaments from squash a couple of times before so i figured yeah prob i do walk a lil funny! checked the soles of my running shoes when i got home and yeah ahha they are a lil worn on the lateral heels bilaterally!! i prob run funny too!!

read couple of articles in the past commenting on heel strike vs forefoot strike, conclusion i drew from them (wrongly! lol i think it was the-select-what-u-read-and co0nclude-what-u-wanna-hear-kinda-reading :x haha) was to do whatever u’re most comfortable with! but anyway just to get the ‘right’ strike, decided to give it a go today. afterall..in primary sch track days, i was taught to land on the ball of my feet when sprinting!

frm my trial today, i do agree the forefoot strike impact is less, but strangely when i changed momentarily back to my usual heel strike, the whole sole of my feet started to feel tingly!..so hmm no idea why (but now i know!). my calves also are tighter now prob cos i;ve never really utilised them that much.

was a lil confused abt what/how the correct strike shd be! but thank God for friends on dailymile! lol


also, found this interesting site -it’s harvard shd be pretty legit! :P http://www.barefootrunning.fas.harvard.edu/4BiomechanicsofFootStrike.html on the mechanics of running (copied and pasted some interesting bits below!)

so yeah my weird walking ankle intorsion seems to be kinda the same way i push off when i do my heel strike runs. so either i always walked like that..or i started to walk more like that after i started to run more 2 years ago!!

Running Kinematics

Heel Striking

Forefoot Striking

Moment of Impact Barefoot Heel Strike Barefoot Forefoot Strike
Hip and knee are flexed.
Ankle is dorsiflexed (toes point up). Ankle is plantarflexed (toes point slightly down). Foot is usually slightly inverted (the sole is angled inwards).
Land on the middle to outside of the heel just below the ankle joint. Land on outside of the forefoot (the ball of the foot, just below the 4th and 5th metatarsal heads).
As you land, the ankle begins to plantarflex (toes move towards the ground). As you land, the ankle begins to dorsiflex (heel moves towards the groud).
Arch of the foot is not loaded. Arch of the foot is loaded and begins tostretch/flatten.
Impact

Foot Flat

Barefoot Heel Strike

Barefoot Foot Flat
Barefoot Forefoot Strike

Barefoot Foot Flat
Knee and hip flex.
As the ankle plantarflexes, the forefoot comes down. As the ankle dorsiflexes, the heel comes down under the control of the calf muscles and Achilles tendon, which are stretching.
Foot Flat

Midstance

Barefoot Foot Flat

Barefoot Midstance
Barefoot Foot Flat

Barefoot Midstance
Knee and hip continue to flex.
The ankle dorsiflexes as the lower leg moves forward relative to the foot and the foot everts (rolls inward).
Now that the whole foot is on the ground, the archbegins to stretch/flatten. The arch continues to stretch/flatten.
This combination of eversion, ankle dorsiflexion and arch flattening is called pronation. This combination of eversion, ankle dorsiflexion and arch flattening is called pronation, but occurs in the reverse direction compared to heel striking (from the forefoot to the rearfoot not heel to toe).
Midstance

Toe Off

Barefoot Midstance

Barefoot Toe Off
Barefoot Midstance

Barefoot Toe Off
Ankle plantarflexes bringing the heel off the ground (calf muscles and Achilles tendon now shorten).
Foot’s arch recoils, and the toes flex.
These actions push the body upwards and forwards for the next stride.

Running Kinetics and Impact Forces

The physics of collisions: The impact of the body with the ground generates an impact force, which equals mass times acceleration
(ma, Newton’s 2nd Law). The mass involved in this collision is whatever portion of the body that comes to a dead stop along with the point of impact on the foot (this is called the effective mass). The acceleration is the rate of change of this mass’ velocity. Because the impact occurs over a brief period of time, the force times the duration of the collision, called theimpulse, is the effective mass times its change in velocity over the duration of the impact. For a detailed explanation of the physics, see equation 1 in Lieberman et al (2010).

Heel Striking

Forefoot Striking

Effective Mass at Impact Foot and lower leg come to a dead stop at impactwhile the rest of the body continues to fall above the knee. Forefoot comes to a dead stop, but the heel and lower leg continue to fall (in a forefoot strike). Theankle flexes (in both forefoot and midfoot strikes).
Effective mass is approximately the foot plus the lower leg, which equals 6.8% of total body mass in the runners measured in Lieberman et al. (2010). Effective mass is the forefoot and some portion of the rearfoot and leg, which equals 1.7% of total body mass in the runners measured in Lieberman et al. (2010).
Change in Velocity at Impact The change in velocity of the effective mass is the difference between the velocity of the falling foot at the instant before contact and the velocity just after contact, which is zero. This change in velocity does not differ significantly between a heel strike and a forefoot strike.
Conversion of Vertical Momentum at Impact Although the ankle may flex a little (plantarflex) during the impact period, the vertical momentum of the lower leg is mostly absorbed by the vertical component of the collision force. Much of the vertical momentum of the rearfoot and lower leg is converted into rotational momentum.
Analogy: It is like dropping a rod straight down on its end: it comes to a sudden, loud stop. Analogy: It is like dropping a rod on its end at an angle: there is a sudden stop at one end of the rod, but it is much less loud because the rest of the rod continues to fall as it topples over.
Impact Force This kind of collision leads to a rapid, high impact transient about 1.5 to as much as 3 times your body weight (depending on your speed) within 50 milliseconds of striking the ground (see graph a below).This is equivalent to someone hitting you on the heel with a hammer using 1.5 to as much as 3 times your body weight. These impacts add up, since you strike the ground almost 1000 times per mile!

Many running shoes make heel strikes comfortable and less injurious because they slow the rate of loading considerably, reduce the force by about 10% (seegraph b below) and spread this force out over a greater area of the foot. But they do not eliminate the impact transient.

This kind of collision produces a very slow rise in force with no distinct impact transient. There isESSENTIALLY NO IMPACT TRANSIENT in a forefoot strike (see graph c below). The same is true of some (but not all) midfoot strikes.We have found that even on hard surfaces (a steel force plate) runners who forefoot strike have impact forces that are 7 times lower than shod runners who heel strike. Rates of loading are equal to or less than rates of loading for shod runners.
Figure 1aFigure 1b Figure 1c
Note that the peak force at midstance is the same for both kinds of gaits. This peak reflects the ground reaction force when the body’s center of mass is at its lowest point. Because peak force at midstance rises slowly, it is probably less related to injury.
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