Saturday, March 20, 2010

Perception of effort, not muscle fatigue, limits endurance performance

"As recently as 2008, scientific research papers were citing the theory that endurance performance is limited by the capacity of the skeletal muscles, heart and lungs and that exhaustion occurs when the active muscles are unable to produce the force or power required by prolonged exercise.
Dr Sam Marcora, an exercise physiologist at Bangor University, has now disproved this for the first time and proposed an alternative - that it is your perception of effort that limits your endurance performance, not the actual capability of your muscles. He showed that the muscles were still able to achieve the power output required by endurance exercise even when the point of perceived exhaustion had been reached".
The idea that the perception of effort limits a person's endurance performance is relevant to any physical activity that requires endurance, not just the sporting arena.

For birthing women, their families and midwives, this information is very important. Perceptions around labour and birth are culturally constructed. Many women are apprehensive about giving birth because of the negativity they are subjected to on a daily basis from well meaning friends, associates and even total strangers. That apprehension that many women feel, coupled with also well meaning but negative, undermining comments when they are in labour, may lead many women to perceive that they are 'at the end of their tether' and unable to go on. Birthing physiology requires the woman to feel safe and loved to work optimally.

Many partners get frightened by the rawness and primal nature of labour and seek to make themselves feel better by sympathising/pitying and/or suggesting pain relief for the labouring woman. An example is regarding one of the couples, several years ago, who came back to an antenatal group to talk about their birth experience six weeks earlier. When they had told their story, the man said "I was so happy when she had the epidural, I couldn't stand it any longer".

Women do look to their partners and caregivers to check how they are 'doing' in labour. Women get feedback that way. Fear-filled or pitying faces trigger mirror neurons to create similar feelings in the women, disrupting their physiological functioning for birthing. Unless the woman's self talk is particularly strong and positively oriented, her mind will be filled with fearful reactive thoughts, further disrupting her birthing physiology.

On the other hand, in a similar way to what happens in sporting situations, when partners/family and midwives provide encouragement, words of praise, smiling faces and a firm belief in the woman's ability, women's self talk changes and they find the inner strength to continue, even getting a 'second wind' as the energy in the room picks up. That's where the analogy to sport ends because with birthing there is no competition. There is no one to beat. The wonder is that there is a beautiful baby and fabulous placenta to welcome into the world.


The recipe for enabling birth, as it is for any physically related endeavor requiring focus and endurance:

  • believe you can 'do it'
  • prepare yourself
  • surround yourself with people who believe in you
  • ask your partner/support people to say supportive messages and to smile at you in labour
  • tell yourself that you 'can'
  • do it

Perception of effort, not muscle fatigue, limits endurance performance

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