{"id":1902,"date":"2019-10-27T22:02:46","date_gmt":"2019-10-27T22:02:46","guid":{"rendered":"https:\/\/drmirkin.com\/?p=1902"},"modified":"2023-07-28T21:46:39","modified_gmt":"2023-07-28T21:46:39","slug":"stretching-doesnt-deliver","status":"publish","type":"post","link":"http:\/\/drmirkin.com\/?p=1902","title":{"rendered":"Stretching Doesn’t Deliver"},"content":{"rendered":"\n

Whenever I see someone stretching before or after hard exercise, I worry that the person has gotten bad advice about training.
\u2022 You should not stretch before a competition because stretching weakens muscles.
\u2022 You should not stretch after hard exercise because stretching muscles that are already damaged by intense exercise delays recovery and increases risk for injury.
\u2022 You cannot lengthen muscles or tendons by stretching.
An extensive review of the scientific literature showed that the supposed benefits of stretching are highly controversial (Int J Sports Phys Ther<\/em>, 2012 Feb; 7(1): 109-119).<\/p>\n\n\n\n

Stretching Does Not Lengthen Muscles<\/strong>
\nYou can make a muscle longer while you are stretching, but after you finish\nstretching, the muscle returns to its former length. A review of 26 studies of\nstretching for 3-8 weeks found that stretching did not elongate muscles or\ntendons. The people were able to stretch further only because they learned to\ntolerate more pain (Scand J Med Sci Sports<\/em>, Mar\n2018;28(3):794-806). People who stretch regularly, such as gymnasts and people\nwho do yoga, can stretch further than non-stretchers because they can tolerate\nmore pain or they have less pain while they stretch (Scan j\nMed & Sci in Sports<\/em>, Feb 2010;20(1):136-144). Stretching a\nmuscle pulls on nerve fibers in the muscle to cause pain, so you stop stretching\nwhen it hurts. When a person is given an anesthetic, he can stretch much\nfurther because he feels less pain. Regular stretchers stretch so often that\nthey feel pain later than non-stretchers do and they learn to tolerate more\npain when they stretch. If muscles did remain stretched, stretching would harm\nyou because the overstretched muscle would lose its elasticity and be much\nweaker. Placing animals in muscle-stretching casts for several weeks can cause\nthe muscles to grow extra units called sarcomeres, but muscles return to their\noriginal length soon after the cast is removed.<\/p>\n\n\n\n

Stretching Does Not Prevent Sports Injuries<\/strong>
\nMuscles and tendons tear when the force applied to them is greater than their\ninherent strength, so anything that makes a muscle stronger helps to prevent\ninjuries. Stretching does not strengthen muscles so it does not prevent\ninjuries such as shin splints, bone stress fractures, sprains or strains (Research\nin Sports Medicine<\/em>, Dec 2, 2016;25(1):78-90).<\/p>\n\n\n\n

Stretching Does Not Prevent Delayed Onset Muscle\nSoreness (DOMS)<\/strong>
\nA review of 12 studies published over the last 25 years shows that stretching\ndoes not prevent delayed\nonset muscle soreness (DOMS)<\/a>, soreness that occurs eight to 24 hours after\nyou exercise vigorously (The British Journal of Sports Medicine<\/em>,\nDecember 2011; 45:15 1249-1250). Researchers in Australia reviewed five\nstudies, involving 77 subjects, to show that stretching does not prevent\nnext-day muscle soreness (British Medical Journal<\/em>, December\n2007; 325:468-70 and 451-2). To enlarge a muscle and make it stronger, you have\nto put enough force on it to damage that muscle, so proper training requires some\ndegree of muscle soreness on the day after an intense workout. Athletes train\nby taking a hard workout, feeling sore the next day, and then taking easy\nworkouts for as many days as it takes for the soreness to go away. Since\nstretching does not reduce muscle soreness, it will not help you to recover\nfaster from hard exercise. The best way to recover from exhausting competition\nis to move with little pressure on muscles, such as cycling on a stationary\nbicycle (American Journal of Physical Medicine & Rehabilitation<\/em>,\nJune 2007).<\/p>\n\n\n\n

How Muscles Move Your Body<\/strong>
\nEvery muscle in your body is made up of thousands of individual fibers. Each\nmuscle fiber is composed of sarcomeres, repeated blocks lined up end-to-end to\nform rope-like fibers. Muscles move your body by contracting which shortens\neach muscle fiber. Muscles do not shorten (contract) equally throughout their\nlengths. Muscles contract only at each of thousands of sarcomeres. It is the\ncumulative shortening of thousands of sarcomeres that shorten fibers to make\nmuscles contract and move your body. A sarcomere contains two proteins: actin\nand myosin. The actin proteins line up between myosin proteins above and below\nthem. The actins slide toward each other to shorten the sarcomere. When\nthousands of sarcomeres shorten together at the same time, the entire muscle\ncontracts.<\/p>\n\n\n\n

Stretching Before Exercising Weakens Muscles<\/strong>
\nStretching before competition and training weakens muscles. Elite college\nsprinters were timed in 20 meter sprints, with and without prior multiple\n30-second stretches of their leg muscles. Both active and passive stretching\nslowed them down (Journal of Sports Science<\/em>, May 2005). Stretching prevents\nyou from lifting your heaviest weights or running your fastest miles. It limits\nhow high you can jump, and how fast you can run (Scand J Med Sci Sports<\/em>,\n2013 Mar;23(2):131-48; J Strength Cond Res<\/em>, 2013,\nApr;27(4):973-7). Stretching weakens muscles temporarily by almost 5.5 percent.\nThe longer you hold the stretch, the more strength you lose. Holding a stretch\nfor more than 90 seconds markedly reduces strength in that muscle. Stretching\nreduces power: how hard you can hit a baseball or tennis ball, or how fast you\ncan swim, run or pedal. When you stretch a muscle, you pull on the muscle\nfibers and stretch apart each fiber at the thousands of Z lines between the\nsarcomeres. This damage occurs only at the Z lines throughout the length of the\nmuscle fiber, to weaken the entire muscle. On the other hand, warming up<\/a> makes\nmuscles more pliable, helps you to run faster and lift heavier, and helps to\nprevent injuries.<\/p>\n\n\n\n

Stretching Does Not “Warm Up” Muscles<\/strong>
\nStretching can never be considered “warming up”. Holding a muscle\ncontraction does not generate much heat and therefore does not warm up muscles.\nWarm up by starting out your exercise slowly and gradually increasing the\nintensity. This raises muscle temperature to make muscles more pliable and\nresistant to injury. Since almost 80 percent of the energy used to power\nmuscles is lost as heat, you must contract and relax muscles continuously to\ngenerate the heat necessary to raise muscle temperature. Warming up before you\nexercise helps to prevent injuries and lets you jump higher, run faster, lift\nheavier or throw further. Your warm-up should involve the same muscles and\nmotions you plan to use in your sport. For example, before you start to run\nvery fast, do a series of runs of gradually-increasing intensity to increase\nthe circulation of blood to the muscles you will be using. If you decide to\ncontinue stretching even after you have read all of my reasons not to, be sure\nto warm up first; do not stretch cold muscles.<\/p>\n\n\n\n

Prolonged Stretching Limits the Ability of\nMuscles to Store Energy<\/strong>
\nMuscles are like rubber bands. They stretch and contract with each muscle\nmovement. This constant stretching and contracting stores energy. For example,\nwhen you run, you land on your foot and the muscle stops contracting suddenly.\nThe force of your foot striking the ground is stored in your muscles and\ntendons and this energy is released immediately to drive you forward. Your foot\nhits the ground with a force equal to three times your body weight when you run\nat a pace of six minutes per mile. Up to 70 percent of the force of your foot\nstrike is stored in your Achilles tendon and other tendons. This energy is\nreleased by your muscles and tendons to drive you forward for your next step.\nStretching decreases the amount of energy you can store in muscles and tendons\nand therefore weakens you and you have less stored energy to drive you forward,\nso you have to slow down.<\/p>\n\n\n\n

Contracting Stretched Muscles May Make Them\nStronger<\/strong>
\nAthletes can become stronger by lengthening their tendons before they contract\nthem. The longer a tendon, the greater the torque the muscle can put on a joint\nand the more force it can generate to make you faster and stronger. Passive\nstretches do not do this. It is more effective to try proprioceptive\nneuromuscular facilitation (PNF), in which the athlete stretches his tendons\nand then tries to contract the muscles from the lengthened position. Gymnasts\nhave been shown to increase their flexibility more after PNF stretching than\nafter static stretching (Journal of Sports Medicine and Fitness<\/em>,\nDecember 2014). Many athletes incorporate plyometrics into their training\nprograms. For example, they jump off a series of steps consecutively. Their leg\ntendons are stretched when they land and they contract their muscles to do\ntheir next jump. However, this has been shown to increase their chances of\ninjury.<\/p>\n\n\n\n

Summing Up<\/strong>
Stretching offers little benefit to regular exercisers. There is some evidence that stretching a contracted muscle may offer a competitive athlete more power when that muscle is contracted, but stretching contracted muscles may increase susceptibility for injuries. Activities such as yoga that involve stretching motions can be beneficial and enjoyable, but they should not be used just before or just after a competition or session of hard exercise.<\/p>\n\n\n\n

Checked 7\/27\/23<\/p>\n","protected":false},"excerpt":{"rendered":"

Whenever I see someone stretching before or after hard exercise, I worry that the person has gotten bad advice about training. You should not stretch before a competition because stretching weakens muscles.<\/p>\n","protected":false},"author":1,"featured_media":1008,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_et_pb_use_builder":"","_et_pb_old_content":"","_et_gb_content_width":"","footnotes":""},"categories":[6],"tags":[100,114,115],"class_list":["post-1902","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-fitness","tag-muscles","tag-stretch","tag-stretching"],"_links":{"self":[{"href":"http:\/\/drmirkin.com\/index.php?rest_route=\/wp\/v2\/posts\/1902","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/drmirkin.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/drmirkin.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/drmirkin.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/drmirkin.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1902"}],"version-history":[{"count":0,"href":"http:\/\/drmirkin.com\/index.php?rest_route=\/wp\/v2\/posts\/1902\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/drmirkin.com\/index.php?rest_route=\/wp\/v2\/media\/1008"}],"wp:attachment":[{"href":"http:\/\/drmirkin.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1902"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/drmirkin.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1902"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/drmirkin.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1902"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}