I boka The Lost Sixth Sense: a medical scientist looks at the Alexander Technique forteller David Garlick om noen fysiologiske mekanismer relevante for Alexanderteknikken. En av de tingene han skriver om er muskler.
I kroppen har du tre typer muskler: skjelettmuskulatur til bevegelse, glatt muskulatur i tarmene og hjertemuskulatur i hjertet. Om skjelettmuskulatur skriver Garlick:
Skeletal muscle is made up of muscle fibres which are actually cells. They have a membrane and a nucleus and chemical reatcions for producing energy. The muscle cell/fibre is specialised for its work. It is a very long cell usually running the length of a muscle and it is packed with parallel arranged fibrils running the length of the cell. These fibrils within the cell/fibre have regularly spaced bands across them, hence the name striated muscle as opposed to smooth or non-striated muscle as found in the gastro-intestinal tract and in blood vessels. The striations are due to the arrangements of the basic units of the fibrils, the myofilaments, which are the units of the contractile process. When the nerve fibre is activated (or it fires) it activates or fires the muscle fibre. This releases calcium in the fibre and causes the repeating units of filaments to “pull” on each other, causing the muscle to increase its tension or to shorten (Garlick, 1990, s. 35).
Skjelettmusklene består av muskelfibre av forskjellige typer. Garlick skriver videre:
There are two main muscle fibre types. In animals there is usually a preponderance of one or other type; that is, the red meat of beef or the white meat of poultry. … The red fibre is not fatiguable (theoretically) because it uses oxygen to burn glucose and fat for energy and it gives off carbon dioxide. White fibres are larger and stronger but fatigue more or less quickly, using up their energy stores and producing lactic acid (ibid, 35-37).
Hos mennesket består musklene av begge typer fibre: «In human beings the two types are ususally evenly mixed in most muscles; most muscles in a majority of people have 50% each of the two fibre types» (ibid, s. 35). Variasjon i distribusjon forekommer. Noe forskning tyder på at mer av de «røde» fibrene ligger dypere og mer av de «hvite» nærmere overflaten i musklene. Dette har antagelig sammenheng med at de ulike muskelfibertypene er tilpasset ulike arbeidsoppgaver:
The red fibres are well suited for sustained contractions necessary for the upright posture, as well as during lower levels of rhythmic contractions. The postural role of the red fibres is important to emhpasize in relation to the Technique; it is perfectly possible to use muscle at low levels necessary to maintain upright position, sitting and standing, without a sense of fatigue. Joints and other non-muscular tissues may give rise to discomfort if a person sits or stands motionless but red muscle fibres themselves will not fatigue (ibid, s. 37).
Garlick forklarer hvordan dette kan henge sammen vanemessig bruk av kroppen:
For the average person with inappropriate muscle function, some muscles may be overcontracted hence bringing into play fatiguable white fibres; other muscles such as the back muscles may be under-used and the red postural fibres are not used adequately and may be atrophied. In the course of lessons the pupil is encouraged to “lengthen and widen” the trunk thereby beginning to use the red postural fibres. If these have not been used and are weak, it will take some time for the red fibres to recover their function and strength (ibid).
Vi kan bruke denne beskrivelsen for å gi en enkel forklaringsmodell for Alexanderteknikken: vi vil bruke bare det helt nødvendige av «hvite» muskelfibre slik at de «røde» fibrene kan utnyttes fullt ut.
Et poeng som Garlick er inne på her er at muskelfibre som ikke er blitt brukt vil atrofere, dvs. bli svakere. Dette forklarer hvorfor noen opplever at det tar tid før de kan sitte oppreist uten støtte i ryggen i en alexandertime. Det er viktig å gi seg selv tid og ikke prøve for hardt å sitte «rett»:
Of course, if the person tries too hard or self-consciously aims to be erect she/he may well become stiff; the result of “end gaining”. Under these circumstances joints and associated tissues will beome uncomfortable and also the white, fatiguable fibres may be activated. The person ends up worse than before. If reflects part of the subtlety of the Technique (ibid).
En modell basert på funksjonen til røde og hvite muskelfibre gir også forklaringen på hvorfor Alexanderteknikken ikke bare handler om «avspenning»: «Thus the Technique is not about relaxation and or relaxing muscles. It is about using muscles, and their component fibres, appropriately and actively while avoiding over-contraction and stiffness» (ibid).
Garlick avslutter avsnittet om muskelfibertyper med å fortelle om sammenhengen mellom muskelspenninger og pust:
A good indication of ‘end-gaining’ and of stiffness is breathing pattern. The more one stiffens or contracts one's muscles the more it tends to make breathing more shallow and quicker or more irregular. Slow deep, relaxed breathing is an indication of appropriate postural use of muscles (ibid).
Pusten er alltid en god indikator på om du bruker for mye av de hvite muskelfibrene på bekostning av de røde.
Relaterte blogginnlegg:
Litteratur:
Garlick, David. 1990. The Lost Sixth Sense. A medical scientist looks at the Alexander Technique. The University of NSW, Australia.
Lenker:
Garlicks bok er ut av trykk, men du kan lese mer i denne artikkelen fra den internasjonale Alexanderteknikk-kongressen i Sydney 1994. Her skriver han om tre ulike typer muskelfibre, om pust, muskelkontroll, og om planlagte eksperimenter:
David Garlick døde dessverre allerede i 2002. I denne artikkelen forteller alexanderlærer Gerald Foley mer om David Garlick og om røde og hvite muskelfibre:
Wikipedia: Types om muscle tissue
Store norske leksikon: Muskelvev
Store norske: Type I- og type II-fibre
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