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Data from: Linking in vivo muscle dynamics to in situ force-length and force-velocity reveals that guinea fowl lateral gastrocnemius operates at shorter than optimal lengths

Cite this dataset

Schwaner, M. Janneke; Mayfield, Dean L; Azizi, Emanuel; Daley, Monica A (2024). Data from: Linking in vivo muscle dynamics to in situ force-length and force-velocity reveals that guinea fowl lateral gastrocnemius operates at shorter than optimal lengths [Dataset]. Dryad. https://doi.org/10.5061/dryad.0p2ngf26p

Abstract

Force-length (F-L) and force-velocity (F-V) properties characterize skeletal muscle’s intrinsic properties under controlled conditions, and it is thought that these properties can inform and predict in vivo muscle function. Here, we map dynamic in vivo operating range and mechanical function during walking and running, to the measured in situ F-L and F-V characteristics of guinea fowl (Numida meleagris) lateral gastrocnemius (LG), a primary ankle extensor. We use in vivo patterns of muscle (tendon) force, fascicle length, and activation to test the hypothesis that muscle fascicles operate at optimal lengths and velocities to maximize force or power production during walking and running. Our findings only partly support our hypothesis: in vivo LG velocities are consistent with optimizing power during work production, and economy of force at higher loads. However, LG does not operate at lengths on the force plateau (±5% Fmax) during force production. LG length was near L0 at the time of EMG onset but shortened rapidly such that force development during stance occurred almost entirely on the ascending limb of the F-L curve, at shorter than optimal lengths. These data suggest that muscle fascicles shorten across optimal lengths in late swing, to optimize the potential for rapid force development near the swing-stance transition. This may provide resistance against unexpected perturbations that require rapid force development at foot contact. We also found evidence of passive force rise (in absence of EMG activity) in late swing, at lengths where passive force is zero in situ, suggesting that history dependent and viscoelastic effects may contribute to in vivo force development. Direct comparison of in vivo work loops and physiological operating ranges to traditional measures of F-L and F-V properties suggests the need for new approaches to characterize dynamic muscle properties in controlled conditions that more closely resemble in vivo dynamics.

README: Data from: Linking in vivo muscle dynamics to in situ force-length and force-velocity reveals that guinea fowl lateral gastrocnemius operates at shorter than optimal lengths

https://doi.org/10.5061/dryad.0p2ngf26p

Description of the data and file structure

Data set name: Data from: “Linking in vivo muscle dynamics to in situ force-length and force-velocity reveal that guinea fowl lateral gastrocnemius operates at shorter than optimal lengths”.
General Information
The dataset contains two specific data files. One is the Matlab files (.mat) that contain continuous in vivo recordings of muscle length, force, and activation for all in vivo individuals (n = 6) during walking and running on the treadmill. The other one (.xsls) contains summary values used to run the statistics of the accompanying manuscript. Below one can find detailed descriptions of these source data and their meaning.
In vivo recordings
Each .mat file contains the in vivo recordings of one trial recorded of an individual while walking (1p5 extension) or running (3p5 extension) on the treadmill. The 1p5 refers to 1.5 mph that corresponds to the setting of the treadmill. This corresponds to 0.67 meters per second. The running speed was 3.5 miles per hour, which corresponds to 1.56 meters per second. Each file also contains corresponding in situ measures for each bird, as well as muscle weight. Detailed descriptions of these data can be found below.

Field Name Value
Ind Individual number.
Speed_ms Locomotion speed in meters per second.
Muscle The muscle of which data was recorded. For this dataset, the only muscle measured is the Lateral Gastrocnemius (LG).
MuscleMass_g Muscle mass in grams.
MuscleForce_N Muscle force in Newtons. Measured through a force buckle for an entire treadmill recording at 5000 Hz.
FascicleLength_mm Fascicle length in millimeters.
EMGfilt Filtered EMG. For details on filtering, see manuscript.
EMGRaw Raw EMG recording. This data is untouched and unfiltered.
Time Time in seconds.
ForceFilter Filtering values for force buckle data.
CutIndex These indexes have been used to cut the data mid-swing to mid-swing. These timings were based on ankle joint kinematics.
UsedStrides These indexes indicate the strides that were used for further analysis. As birds did not always continue steady locomotion, unsteady strides were cut from further analysis.
FootOn Indexes that correspond with time of foot on.
FootOff Indexes that correspond with time of foot off.
Fmax_N Maximum force measured through 200 ms isometric contractions In situ.
L0_mm Optimal active length in millimeters.
Vopt_Lfs Optimal shortening velocity in fascicle lengths per second.
Vmax_Lfs Maximal shortening velocity in fascicle lengths per second.

 
Data used for statistics
This Excel file contains the values (originating from the in vivo and in situ data presented in the manuscript) that were used to run the statistical tests. To run the appropriate statistical test averages were calculated for each individual, before generating group averages.
Sheet 1 contains all animal measurements. Sheet 2 contains the measures used for the statistical tests.
Units for each value are reported in the Excel spreadsheet.

Field Name Value
Ind Individual number
Mph Locomotor speed in miles per hour (corresponding to treadmill settings).
L_EMGon_L0 Muscle fascicle length (L) at time of EMG on (EMGon) in optimal lengths (L0).
Std_L_EMGon_L0 Standard deviation (Std) of the muscle length (L) at time of EMG on (EMGon) in optimal lengths (L0).
F_EMGon_Fmax Muscle force (F) at time of EMG on (EMGon) in fractional LG force (Fmax). Fractional force is calculated by dividing LG muscle force (in vivo) by maximum LG force (in situ).
Std_ F_EMGon_Fmax Standard deviation (Std) of the muscle force (F) at time of EMG on (EMGon) in fractional force (Fmax).
F_Ton_Fmax Force (F) at time of foot on (Ton) in fractional LG force (Fmax)
Std_F_Ton_Fmax Standard deviation (Std) of the force (F) at time of foot on (Ton) in fractional LG force (Fmax)
L_Fpk_L0 Fascicle length (L) at time of peak force (Fpk) in optimal lengths (L0).
Std_L_Fpk_L0 Standard deviation (Std) of the fascicle length (L) at time of peak force (Fpk) in optimal lengths (L0).
F_Fpk_Fmax Force (F) at time of peak force (Fpk) in fractional LG force (Fmax)
std_F_Fpk_Fmax Standard deviation (Std) of the force (F) at time of peak force (Fpk) in fractional LG force (Fmax)
L_Frise_L0 Fascicle length (L) at time of force rise (Frise) in optimal lengths (L0).
std_L_Frise_L0 Standard deviation (Std) of the fascicle length (L) at time of force rise (Frise) in optimal lengths (L0).
F_Frise_Fmax Force (F) at time of force rise (Frise) in fractional LG force (Fmax)
std_F_Frise_Fmax Standard deviation (Std) of the force (F) at time of force rise (Frise) in fractional LG force (Fmax)
L_Ffall_L0 Fascicle length (L) at time of force fall (Ffall) in optimal lengths (L0).
std_L_Ffall_L0 Standard deviation (Std) of the fascicle length (L) at time of force fall (Ffall) in optimal lengths (L0).
F_Ffall_Fmax Force (F) at time of force fall (Ffall) in fractional LG force (Fmax)
std_F_Ffall_Fmax Standard deviation (Std) of the force (F) at time of force fall (Ffall) in fractional LG force (Fmax)
V_Fpk_L0 Shortening velocity (V) at time of peak force (Fpk) in optimal lengths (L0) per second.
std_V_Fpk_L0 Standard deviation (Std) of the shortening velocity (V) at time of peak force (Fpk) in optimal lengths (L0) per second.
V_Ton_L0 Shortening velocity (V) at time of foot on (Ton) in optimal lengths (L0) per second.
std_V_Ton_L0 Standard deviation (Std) of the shortening velocity (V) at time of foot on (Ton) in optimal lengths (L0) per second.

 

Funding

National Science Foundation, Award: 2016049

National Institute on Aging, Award: R01 AR055295-09