Connective tissue is composed of a base substance and two kinds of protein based fiber. The two types of fiber are collagenous connective tissue and elastic connective tissue. Collagenous connective tissue consists mostly of collagen hence its name and provides tensile strength. Elastic connective tissue consists mostly of elastin and as you might guess from its name provides elasticity.
The base substance is called mucopolysaccharide and acts as both a lubricant allowing the fibers to easily slide over one another , and as a glue holding the fibers of the tissue together into bundles. The more elastic connective tissue there is around a joint, the greater the range of motion in that joint.
Connective tissues are made up of tendons, ligaments, and the fascial sheaths that envelop, or bind down, muscles into separate groups. These fascial sheaths, or fascia , are named according to where they are located in the muscles: endomysium The innermost fascial sheath that envelops individual muscle fibers.
These connective tissues help provide suppleness and tone to the muscles. Cooperating Muscle Groups Types of Muscle Contractions : next section Connective Tissue : previous section Physiology of Stretching : beginning of chapter When muscles cause a limb to move through the joint's range of motion, they usually act in the following cooperating groups: agonists These muscles cause the movement to occur.
They create the normal range of movement in a joint by contracting. Agonists are also referred to as prime movers since they are the muscles that are primarily responsible for generating the movement. Synergists are sometimes referred to as neutralizers because they help cancel out, or neutralize, extra motion from the agonists to make sure that the force generated works within the desired plane of motion.
Fixators are also sometimes called stabilizers. As an example, when you flex your knee, your hamstring contracts, and, to some extent, so does your gastrocnemius calf and lower buttocks. Meanwhile, your quadriceps are inhibited relaxed and lengthened somewhat so as not to resist the flexion see section Reciprocal Inhibition.
In this example, the hamstring serves as the agonist, or prime mover; the quadricep serves as the antagonist; and the calf and lower buttocks serve as the synergists. Agonists and antagonists are usually located on opposite sides of the affected joint like your hamstrings and quadriceps, or your triceps and biceps , while synergists are usually located on the same side of the joint near the agonists.
Larger muscles often call upon their smaller neighbors to function as synergists. Muscles can contract in the following ways: isometric contraction This is a contraction in which no movement takes place, because the load on the muscle exceeds the tension generated by the contracting muscle.
This occurs when a muscle attempts to push or pull an immovable object. This occurs when you use your muscles to successfully push or pull an object. Isotonic contractions are further divided into two types: concentric contraction This is a contraction in which the muscle decreases in length shortens against an opposing load, such as lifting a weight up.
During a concentric contraction, the muscles that are shortening serve as the agonists and hence do all of the work. During an eccentric contraction the muscles that are lengthening serve as the agonists and do all of the work. See section Cooperating Muscle Groups. What Happens When You Stretch Types of Muscle Contractions : previous section Physiology of Stretching : beginning of chapter The stretching of a muscle fiber begins with the sarcomere see section Muscle Composition , the basic unit of contraction in the muscle fiber.
As the sarcomere contracts, the area of overlap between the thick and thin myofilaments increases. As it stretches, this area of overlap decreases, allowing the muscle fiber to elongate. Once the muscle fiber is at its maximum resting length all the sarcomeres are fully stretched , additional stretching places force on the surrounding connective tissue see section Connective Tissue.
As the tension increases, the collagen fibers in the connective tissue align themselves along the same line of force as the tension. Hence when you stretch, the muscle fiber is pulled out to its full length sarcomere by sarcomere, and then the connective tissue takes up the remaining slack.
When this occurs, it helps to realign any disorganized fibers in the direction of the tension. This realignment is what helps to rehabilitate scarred tissue back to health. When a muscle is stretched, some of its fibers lengthen, but other fibers may remain at rest. The current length of the entire muscle depends upon the number of stretched fibers similar to the way that the total strength of a contracting muscle depends on the number of recruited fibers contracting.
According to SynerStretch you should think of "little pockets of fibers distributed throughout the muscle body stretching, and other fibers simply going along for the ride".
This is beneficial because your muscles need oxygen to function, and blood cells bring oxygen to your muscles. Performing stretches may also help you increase your strength when lifting weights and improve your endurance when performing cardiovascular activity.
Brian Willett began writing in Share on Facebook. Does Stretching Elongate Muscles? Stretching once today won't magically give you perfect flexibility. You'll need to do it over time and remain committed to the process. A hamstring stretch will keep the muscles in the back of your thigh flexible.
Sit on the floor with your legs in front of you. Slide your hands down your legs until you feel a burning sensation. Hold for 30 seconds, then slowly return to a sitting position.
We used to believe that stretching was necessary to warm up the muscles and prepare them for activity. However, mounting research has shown that stretching the muscles before they're warmed up can actually hurt them. If you exercise first, you'll get blood flow to the area, and that makes the tissue more pliable and amenable to change," says Nolan.
All it takes to warm up the muscles before stretching is five to 10 minutes of light activity, such as a quick walk. You can also stretch after an aerobic or weight-training workout.
Hold a stretch for 30 seconds. Don't bounce, which can cause injury. You'll feel tension during a stretch, but you should not feel pain.
If you do, there may be an injury or damage in the tissue. Stop stretching that muscle and talk to your doctor. There is historical tradition saying that stretching has been practiced for thousands of years, mostly by warriors before combat Behm, We do not know the preferred stretching technique during the early days; however, today four main stretching techniques i.
Specifically, static stretching StS involves a controlled continuous movement to the end range-of-motion ROM of a single joint or multiple joints by either actively contracting the agonist muscles i. In the end position, the individual holds the muscle in a lengthening position for a certain time Behm et al. Even though StS has widespread usage, it is also the most controversially debated technique with constantly changing views on its positive and negative effects on muscle strength and power.
The general belief that spread from the World Wars until the s is that StS promoted flexibility and improved athletic performance Behm, This was mainly substantiated by the thought that greater ROM reduces resistance to movement and improves movement economy Behm, However, since the late s up to early s, researchers have started discussing the potential harmful effects of StS on subsequent strength- and power-related activities Behm et al.
More recently, new evidence on StS challenged the view that it should not be conducted pre-exercise Behm et al. More recent findings demonstrated that when included in a full warm-up routine, short-duration StS does not impair subsequent strength and power performances Blazevich et al. The question arises as to the underlying mechanisms responsible for StS-induced impairments in subsequent strength and power activities.
It seems that the contradictory and constantly changing reports with regard to StS research may cause confusion, particularly with coaches and practitioners.
Information from this review may enable readers to better understand the development of StS research and to refresh their knowledge related to previous controversies.
In the end, the authors provide cohort-specific e. This review included studies that examined the acute effects of StS on subsequent strength and power performances. The following key words were used either separately or combined: static stretching, chronic effects, physical performance, strength, power, and injury. Only studies that fulfilled the following inclusion criteria were included in this review: 1 the study addressed a research question related to the acute effects of StS on strength and power performances and 2 included healthy active or competitive individuals studies conducted with seniors were excluded ; 3 the main outcome was a performance or physiological measure; and 4 original or review study written in English and published in a peer-reviewed journal.
Pre-exercise StS for the purpose of strength and power performance improvements has widely been criticized Pope et al. In fact, a large body of scientific evidence has recommended not to use StS immediately before the performance of strength- and power-related activities Shrier, a ; McHugh and Cosgrave, ; Simic et al. This is based on evidence showing acute stretch-related declines in muscle strength and power. For instance, Fowles et al. Likewise, Behm and Kibele studied the effects of four sets of 30 s each with 30 s of rest of different StS intensities i.
In a systematic literature review, Shrier a concluded that StS could be harmful to subsequent strength and power actions. In another systematic review, Behm and Chaouachi suggested that StS has to be implemented with caution if high-speed, power-related activities are required from high-performance athletes. Simic et al. According to these results, the authors recommended not to apply StS during a warm-up routine.
These authors concluded that there is ample evidence to suggest that StS should be avoided before activities that require maximal efforts e. Furthermore, guidelines from the American College of Sports Medicine recommended not to include StS as an integral part of a warm-up routine Garber et al. Several original articles, systematic reviews, and meta-analyses examined the acute effects of StS on strength- and power-related actions over the past years Kay and Blazevich, ; Behm et al.
Recently, Palmer et al. These authors observed significant declines in muscle power s post-StS but not after 30 and 60 s. Caldwell et al. Pulverenti et al. Authors observed a significant decrement in maximal voluntary plantar flexion torque after StS. However, the same authors demonstrated that StS for less than 45 s can be used during warm-up routines without any significant risk of harmful effects on strength and power performances.
Four years later, Behm et al. Overall, the negative acute effects of StS have to be interpreted from a dose-response perspective. These findings contradict the widespread opinion that StS inhibits performance in strength- and power-related activities.
Recent evidence illustrates that it is primarily a matter of total stretching duration Kay and Blazevich, ; Behm et al. A major issue that may confound the external validity of the previous studies is that StS was mostly applied in these studies as a single-mode intervention or in the form of an isolated component during a warm-up program.
However, this is a rather laboratory-based or artificial form of StS application. In training practice, StS is most often part of an integrated full dynamic warm-up program Taylor et al. Recently, Reid et al. The authors revealed that while all stretch durations improved ROM, clear reductions in strength and power measures were found with s of StS per muscle group. The same authors suggested to include StS in a pre-exercise warm-up program because it has the potential to lower the risk of sustaining musculotendinous injuries Woods et al.
Additionally, Bengtsson et al. These authors demonstrated no negative effects of StS on isokinetic muscle performance when followed by sport-specific exercises Bengtsson et al.
Furthermore, in a randomized controlled crossover study, Blazevich et al. These authors observed no negative effects of short-duration StS on power performance. Accordingly, and with reference to previous findings Witvrouw et al. Furthermore, participants in the Blazevich et al. A positive psychological outlook is an important component of optimal performance.
It has previously been shown that the neural system is affected by longer duration StS Trajano et al. For instance, Avela et al. Likewise, Fowles et al. These modulated neural mechanisms are likely to be associated with the observed decrease in strength and power performances Avela et al. Additionally, Marek et al. Further, Trajano et al. The decrease in muscle activation was illustrated by a reduction in EMG amplitude and V-wave a variant of the H-reflex providing insight into the voluntary drive to the motoneurons Trajano et al.
The authors revealed that the rate of EMG rise i. Mitchell et al. Accordingly, it appears logical to state that the decreases in the rate of EMG rise after long-duration StS is due to potential impairments in these physiological characteristics. The difference between the study of Caldwell et al. Particularly, in the Caldwell et al.
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