What is the clinical evidence from this study?

Intervention: Measurement of velocity of unloaded shortening (V0) and force-velocity relation. Primary outcome: Velocity of unloaded shortening (V0) and force-velocity relation along the length of single fibres.

What question did this study set out to answer?

To measure the unloaded shortening velocity (V0) and force-velocity relationships across consecutive segments along the entire length of isolated single frog muscle fibres.

August 1, 1985The Journal of PhysiologyOpen Access

Differences in maximum velocity of shortening along single muscle fibres of the frog.

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Key result

The velocity of unloaded shortening varied along the length of single frog muscle fibres, with highest values near the proximal end, and was inversely related to the curvature of the force-velocity relation.

Key Points

To measure the unloaded shortening velocity (V0) and force-velocity relationships across consecutive segments along the entire length of isolated single frog muscle fibres.
Isolated single muscle fibres from the tibialis anterior of Rana temporaria and segmented them using surface markers spaced 0.5–0.8 mm apart from tendon to tendon.
Used a photoelectric recording system to monitor segment length changes during isotonic release between 2.2 and 2.0 µm sarcomere lengths during fused tetani at 0.5–2.0 °C.
Assessed unloaded velocity and force-velocity relationships across 32 fibre preparations (with 14 complete anatomical orientation experiments).
Unloaded shortening velocity (V0) varied significantly along single fibres, with the difference between highest and lowest values averaging 23 ± 2% of the fibre mean (range 11–45%, n=32).
V0 was consistently higher near the proximal end of the fibre and decreased toward the distal end in 14 complete experiments, independent of force production capacity or passive viscoelastic properties.
Segmental force-velocity data fit Hill's equation well below 80% tetanic force, showing an inverse correlation between V0 and force-velocity curvature (alpha/P0: r = -0.72, P < 0.005, regression V0 = 3.21 - 3.22 * [alpha/P0]).

Structured PICO

Population

32 single muscle fibres isolated from the tibialis anterior muscle of Rana temporaria.

Exposure

Measurement of velocity of 'unloaded' shortening (V0) and force-velocity relation during fused tetani in short successive segments

Outcome

Velocity of 'unloaded' shortening (V0) and force-velocity relation along the length of the fibre

The kinetic properties of the myofilament system differ from one region to another along the length of a single skeletal muscle fibre.

Discussion

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Implication

Challenges uniform fiber assumptions in muscle models; leaves open translation to cardiac mechanics in mammals.

Cite This Study

Edman et al. (1985) studied this question. Measurement of velocity of unloaded shortening (V0) and force-velocity relation was evaluated on Velocity of unloaded shortening (V0) and force-velocity relation along the length of single fibres. The velocity of unloaded shortening varied along the length of single frog muscle fibres, with highest values near the proximal end, and was inversely related to the curvature of the force-velocity relation.

synapsesocial.com/papers/6a659c875459d5adcc337c68 https://doi.org/10.1113/jphysiol.1985.sp015764

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Differences in maximum velocity of shortening along single muscle fibres of the frog.

Key Points

Structured PICO

Discussion

Implication

Cite This Study

Differences in maximum velocity of shortening along single muscle fibres of the frog.

Key Points

Structured PICO

Discussion

Implication

Cite This Study

Also Consider

Also Consider