Length tension relationship frog muscle structure

Length tension relationship – Strength & Conditioning Research

length tension relationship frog muscle structure

ABSTRACT The sarcomere pattern and tension of isolated resting frog atrial evolves from the sliding hypothesis of contraction of skeletal muscle and de- muscle bundle without alteration of either the length or tension of the tissue. The. the familiar linear descending limb of the length-tension relation. length dispersion during contraction appears unable to account for the slow rise of The sarcomere length-tension relation in the toe muscle of the frog. An a priori model of the whole active muscle length-tension relationship was constructed . Sample record of muscle force (N) recordings from an isometric contraction .. potentiation of frog muscle fibres at sarcomere lengths below optimum.

Investigation of supraspinatus muscle architecture following concentric and eccentric training. Journal of Science and Medicine in Sport. Impact of range of motion during ecologically valid resistance training protocols on muscle size, subcutaneous fat, and strength.

Eccentric torque-producing capacity is influenced by muscle length in older healthy adults.

Sarcomere length-tension relations of frog skinned muscle fibres at lengths above the optimum.

The effects of repeated active stretches on tension generation and myoplasmic calcium in frog single muscle fibres. The Journal of Physiology, Pt 3 Changes in muscle architecture and performance during a competitive season in female softball players.

Effects of isometric quadriceps strength training at different muscle lengths on dynamic torque production. Journal of sports sciences, 33 18 Changes in the angle-force curve of human elbow flexors following eccentric and isometric exercise. European journal of applied physiology, 93 Effects of eccentric strength training on biceps femoris muscle architecture and knee joint range of movement.

European Journal of Applied Physiology, 6 Effects of eccentrically biased versus conventional weight training in older adults. Effect of resistance training on skeletal muscle-specific force in elderly humans. Journal of Applied Physiology, 96 3 Differential adaptations to eccentric versus conventional resistance training in older humans.

Experimental physiology, 94 7 Muscle architecture and strength: Early skeletal muscle hypertrophy and architectural changes in response to high-intensity resistance training. Journal of Applied Physiology, 1 Quantitative analysis of sarcomere non-uniformities in active muscle following a stretch. Contraction type influences the human ability to use the available torque capacity of skeletal muscle during explosive efforts. Proceedings of the Royal Society B: Biological Sciences, Damage to human muscle from eccentric exercise after training with concentric exercise.

The Journal of Physiology, Pt 2 Effects of repeated eccentric contractions on structure and mechanical properties of toad sartorius muscle. Shift of peak torque angle after eccentric exercise. International journal of sports medicine, 29 3 The stimulating electrodes are attached to a Narishige micromanipulator on a stand behind the frog; adjust the electrode pair so the sciatic nerve can be elevated over both electrodes. Make sure no extraneous tissue shorts out the stimulation clear view underneath the raised nerve.

Use single shocks to watch the leg twitch. If you don't see a strong twitch when you stimulate, check the settings on the stimulator, and check that the sciatic nerve is lifted up and electrically isolated on the stimulating electrodes. To begin with, we won't care to isolate only the fiber headed for the muscle in quesion--we'll watch the whole leg twitch. Notice where the stimulator "trigger" and the 'scope are connected on the NI rack box; make appropriate matches in your VI for recording the twitch.

  • Muscles are Stretched at Rest
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What is the latency in msec from stimulation to contraction start? What is the duration of a twitch? Slowly increase the stim. One lab partner will move the force transducer micromanipulator and flick the stimulator switch.

The other partner will call out "ready, go" when the VI has started its search for a trigger, and will record max and min responses on an EXCEL spreadsheet.

To insure response over the full range, offset the scope to a negative voltage, so the scope itself doesn't saturate its output. Start with a relaxed setting in which you see no twitch. Don't change the 'scope gain once you start recording data.

Stretch by 1 mm at a time and keep repeating the stimulation.

length tension relationship frog muscle structure

You should get to a state of stretch in which the size of the twitch decreases from maximum. You may have to stop at a point where the force transducer has reached its maximum limit. How repeatable is the data? Can you notice fatigue or creep of the muscle? Make sure you have length going "the right direction" from short to long.

Arrange that the length where the twitch is first nonzero is the rest length of the muscle. Is there any part of the curve with a negative slope? Subtract passive from total to see the active-only LT curve.

Length - Tension Relationship (Video 2.6) - PhysioStasis

Was there any influence on the passive data of a "stretch reflex" mediated by the spinal cord? Or evidence of plastic deformation? If there is time, insert the pin electrodes from the Blaberus Lab into the gastrocnemius muscle and observe the EMG waveform that results from a twitch-causing stimulation.

Can you reassemble the preamp circuit if some wires are removed? Explain how sliding filament theory accounts for negative L-T curve. Explain how sliding filament theory accounts for L-T curve below L0. Now, let's stretch the muscle a little bit, so we increased its resting length by just 1mm. As you can see below, the muscle contracts with more force at this longer resting length.

If we stretch the muscle once again to now 2mm beyond what it was originally, it develops even more force.

length tension relationship frog muscle structure

Stretching the muscle by 1mm allows for more force generation. However, if we stretch the muscle 3mm beyond the original length, now the force developed is less. When we stretch the muscle 4mm, the muscle force development is even less.

Sarcomere length-tension relations of frog skinned muscle fibres at lengths above the optimum.

At a certain stretch, the force generation will begin to decrease. Our results can be graphed to illustrate the resting length on the x-axis versus the tension or force development on the y-axis. As you can see, tension development increases as we increase the resting length to a point, and then tension or force development decreases with further stretch. As it turns out, the resting length that produces maximum tension just so happens to be the resting length of the frog's muscle in the body.

The resting length of our muscles produces maximum tension. Microscopic Anatomy We need to look at the minute details of skeletal muscle cells in order to understand this relationship between resting fiber length and contraction.

Specifically, we need to examine the contents of a sarcomere, which is the functional unit of a striated muscle.