Limits...
Reciprocal activation of gastrocnemius and soleus motor units is associated with fascicle length change during knee flexion.

Lauber B, Lichtwark GA, Cresswell AG - Physiol Rep (2014)

Bottom Line: A concomitant increase in SOL MU activity was observed while no change in the length of its fascicles was found.The opposite effects were found when the knee was moved into extension.A strong correlation (ICC = 0.78) was found between the fascicle length at which MG MUs were de-recruited and subsequently re-recruited.

View Article: PubMed Central - PubMed

Affiliation: Department of Sport and Sport Science, University of Freiburg, Freiburg, Germany.

No MeSH data available.


Group mean average of the normalized fascicle length. Data for fascicle length are plotted against knee angle for medial gastrocnemius (MG, A) and soleus (SOL, B). Gray‐shaded area represents ± standard error of the mean about the mean. During the course of the knee flexion, MG fascicle length decreased followed by an increase during knee extension. SOL fascicle length remained relatively unchanged throughout the flexion–extension cycle.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4208651&req=5

fig03: Group mean average of the normalized fascicle length. Data for fascicle length are plotted against knee angle for medial gastrocnemius (MG, A) and soleus (SOL, B). Gray‐shaded area represents ± standard error of the mean about the mean. During the course of the knee flexion, MG fascicle length decreased followed by an increase during knee extension. SOL fascicle length remained relatively unchanged throughout the flexion–extension cycle.

Mentions: Grouped data revealed that MG muscle fascicle length decreased by 3.5 ± 1.9 mm (P ≤0.05) during the course of knee flexion. MG fascicles increased to their starting length during knee extension; however, hysteresis was evident in the grouped data with slightly longer MG fascicle lengths occurring during flexion than extension for the same knee angle (Fig. 3A showing normalized data). Negligible length change was seen in SOL fascicles with grouped data resulting in a length change of 1.0 ± 0.2 mm over the complete cycle (Fig. 3B showing normalized data). Subjects were able to maintain a constant submaximal plantar flexion torque across both movement phases, with no statistical difference (P =0.6) in plantar flexion torque between the flexion and extension phases (3.8 ± 0.6 Nm and 3.9 ± 0.8 Nm, respectively).


Reciprocal activation of gastrocnemius and soleus motor units is associated with fascicle length change during knee flexion.

Lauber B, Lichtwark GA, Cresswell AG - Physiol Rep (2014)

Group mean average of the normalized fascicle length. Data for fascicle length are plotted against knee angle for medial gastrocnemius (MG, A) and soleus (SOL, B). Gray‐shaded area represents ± standard error of the mean about the mean. During the course of the knee flexion, MG fascicle length decreased followed by an increase during knee extension. SOL fascicle length remained relatively unchanged throughout the flexion–extension cycle.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4208651&req=5

fig03: Group mean average of the normalized fascicle length. Data for fascicle length are plotted against knee angle for medial gastrocnemius (MG, A) and soleus (SOL, B). Gray‐shaded area represents ± standard error of the mean about the mean. During the course of the knee flexion, MG fascicle length decreased followed by an increase during knee extension. SOL fascicle length remained relatively unchanged throughout the flexion–extension cycle.
Mentions: Grouped data revealed that MG muscle fascicle length decreased by 3.5 ± 1.9 mm (P ≤0.05) during the course of knee flexion. MG fascicles increased to their starting length during knee extension; however, hysteresis was evident in the grouped data with slightly longer MG fascicle lengths occurring during flexion than extension for the same knee angle (Fig. 3A showing normalized data). Negligible length change was seen in SOL fascicles with grouped data resulting in a length change of 1.0 ± 0.2 mm over the complete cycle (Fig. 3B showing normalized data). Subjects were able to maintain a constant submaximal plantar flexion torque across both movement phases, with no statistical difference (P =0.6) in plantar flexion torque between the flexion and extension phases (3.8 ± 0.6 Nm and 3.9 ± 0.8 Nm, respectively).

Bottom Line: A concomitant increase in SOL MU activity was observed while no change in the length of its fascicles was found.The opposite effects were found when the knee was moved into extension.A strong correlation (ICC = 0.78) was found between the fascicle length at which MG MUs were de-recruited and subsequently re-recruited.

View Article: PubMed Central - PubMed

Affiliation: Department of Sport and Sport Science, University of Freiburg, Freiburg, Germany.

No MeSH data available.