Isometric functioning of the extrinsic toe flexors during gait

NewsBot · Jun 6, 2013

Members do not see these Ads. Sign Up.
Experimental evidence supporting isometric functioning of the extrinsic toe flexors during gait.
Hofmann CL, Okita N, Sharkey NA.
Clin Biomech (Bristol, Avon). 2013 Jun 1.

BACKGROUND:
The extrinsic toe flexors, flexor hallucis longus and flexor digitorum longus, play an important role in stabilizing the longitudinal arch and supporting high forefoot loads during the stance phase of gait. It was hypothesized that these muscles function isometrically during stance, a strategy thought to provide efficient energy transfer across adjoining body segments, but one for which there is little direct experimental evidence in vivo or in situ.

METHODS:
Eight lower extremity cadavers were loaded into a robotic apparatus that simulates the kinematics and extrinsic muscle activity of the foot and distal tibia during the stance phase of gait. Instantaneous tendon excursions and forces of the extrinsic toe flexors, as well as plantar pressure distributions during stance, were measured under two muscle control strategies: (1) force feedback control, where tendon forces were matched to forces predicted from normal electromyographic patterns and (2) isometric displacement control, where the representative myotendinous junction was held in a constant location.

RESULTS:
Tendon excursions of the flexor hallucis longus (7.18 (1.75)mm) and flexor digitorum longus (6.32 (1.74)mm) under force feedback control were small relative to optimal muscle fiber length (13.6% and 14.2%, respectively). Instantaneous tendon forces and plantar pressure variables were not different (P=0.112-0.912) between the two different muscle control strategies for either muscle.

INTERPRETATION:
These findings suggest that the extrinsic toe flexors function isometrically during the stance phase of gait in vivo.
Click to expand...

Athol Thomson · Jun 6, 2013

NewsBot said: ↑

Experimental evidence supporting isometric functioning of the extrinsic toe flexors during gait.
Hofmann CL, Okita N, Sharkey NA.
Clin Biomech (Bristol, Avon). 2013 Jun 1.
Click to expand...

Interesting.....This makes sense for walking but maybe not for other tasks like jumping.

The paper below is a great summary of how the triceps surae can function isometrically to allow the stretch and recoil of the Achilles tendon when walking. Work done by tendons is less metabolically expensive than work done by muscles. But the muscles must generate adequate isometric force to allow the tendon to operate in this springy manner!

http://jeb.biologists.org/content/214/3/353.full.pdf

Admin2 · Jun 8, 2013

Related Threads:
Other threads tagged with muscle function
The potential of toe flexor muscles to enhance performance
Isometric function of the flexor hallucis longus muscle in normal gait

Sicknote · Jun 8, 2013

NewsBot said: ↑

INTERPRETATION: These findings suggest that the extrinsic toe flexors function isometrically during the stance phase of gait in vivo.
Click to expand...

So I take it when considering exercise selection, you should favour isometric exercises as opposed to dynamic?.

Athol Thomson said: ↑

Interesting.....This makes sense for walking but maybe not for other tasks like jumping.

The paper below is a great summary of how the triceps surae can function isometrically to allow the stretch and recoil of the Achilles tendon when walking. Work done by tendons is less metabolically expensive than work done by muscles.
Click to expand...

From what I gather the tendons do very little when walking, it's only when one starts to run/sprint. Upto 6-7 m/s the contractile components alone are responsible for power output of muscle. Above (7-10.4 m/s+, the contractile components that are responsible for power output of energy is stored in the elastic elements.

Athol Thomson said: ↑

But the muscles must generate adequate isometric force to allow the tendon to operate in this springy manner!
Click to expand...

What happens if the tendons are overly stiff?.

NewsBot · Nov 2, 2015

Adding adaptable toe stiffness affects energetic efficiency and dynamic behaviors of bipedal walking.
Sun S et al
J Theor Biol. 2015 Oct 28

In human walking, toes play an important role in supporting the body and controlling the forward motion. These functions are achieved by muscles and tendons around toe joints. To further understand the importance of toe and how toe muscle functions affect the locomotion, we employ a simple bipedal walking model with compliant joints. The ankle joints and toe joints are modeled as torsional springs and the actuation patterns are similar to that of normal human walking. Experimental results show that adding adaptable compliant toe joints could benefit the stability and energy efficiency. By generating plantar flexion moment after heel-off, the toes contribute to stabilize the body and control the forward motion. In addition, multi-joint foot structure could improve the energy efficiency by reducing the energy consumption of ankle joints. A proper toe actuation pattern could result in a proper toe dorsiflexion and reduce the maximal ankle plantar flexion, leading to a smoother and more efficient locomotion.
Click to expand...

NewsBot The Admin that posts the news.

Athol Thomson Active Member

Admin2 Administrator Staff Member

Sicknote Active Member

NewsBot The Admin that posts the news.

Ankle Isometric Plantar Flexion Strength Test

Immediate and Short-Term Effects of Short- and Long-Duration Isometric Contractions in Patellar Tend

Relation between the ankle joint angle and the maximum isometric force of the toe flexor muscles

Is the short foot exercise primarily an isometric exercise ?

Discharge properties of abductor hallucis before, during and after an isometric fatigue task.

Isometric calf raises for achilles teninopathy (as opposed to eccentric heel drop stretches)

Isometric function of the flexor hallucis longus muscle in normal gait

Share This Page