How will pregnancy affect the body?
Pregnancy will affect each individual woman slighly differenly. However, som key adaptations to the body will affect all women.
The pelvic floor muscles
These muscles run from the front to the back of the pelvis, forming a ‘floor’ across the base of the pelvis. When these muscles are weak, urine may leak out when the woman coughs, squats widely, or performs activities that involve jumping. When they are strong it should be possible to cough and jump with legs out to the side (a Jumping Jack) at the same time with no leak of urine. During pregnancy the weight of the baby presses against, and places a stress on, these muscles. During birth an even greater stress is places on them. Therefore, the inclusion of specific exercises to strengthen the pelvic floor muscles is essential both during and after pregnancy, through everyone can benefit from keeping these muscles strong.
The abdominal muscles
The abdominal muscles must stretch and lengthen to accommodate the growing baby. Great care should be taken with any abdominal work when the baby starts to show. Intense abdominal exercises and too much abdominal work at this time can place too much stress on the abdominal muscles, so avoid such activities.
During pregnancy greater emphasis should be placed on contracting the muscles to fixate the spine and maintain correct posture. If the abdominal muscles are stressed, it is possible for them to separate down their mid-lane (linea alba). This condition is know post-natally as ‘diastasis recti’. (Note: separation of the abdominal muscles is a normal physiological response to pregnancy.) The advice is for participants to work carefully: generally, it is unlikely that exercise in water would cause over-stress.
Osnce separation has occurred, even greater care is needed for the abdominal: it will be more difficult to regain the figure, and the mother may be left with a permanently rounded tummy. The abdominal muscles should be checked regularly after birth, and any exercise which causes the abdominals to dome should be avoided.
To test for separation of the abdominals:
Lie on the floor with the knees bend, and lift the head. If separation has occurred, a gap may be apparent down the middle of the abdomen. A further check can be provided by placing two fingers widthways into the midline of the abdominals, just above or below navel level.
The pelvic girlde becomes lee stable during pregnancy. This is due to the release of a hormone called relaxin that loosens the ligaments around the pelvis in preparation for birth. Any movements involveing the pelvis should either be avoided or performed with great care during pregnancy.
Relaxin may also affect other joints such as the knees, fingers, hips and spine. Care must be taken not to exceed the range of motion at any joint, to prevent permanent damage occurring to the ligaments that will result in the joints becoming less stable. It is essential that correct exercise techniques is emphasized throughout the ante- or post-natal exercise session.
Тhe weight of the growing baby will place extra strain on the lumbar spine. This may result in a forward tilt of the pelvis that will cause the lumbar spine to hollow. In addition, the center of gravity will alter and will affect balance. The mother may develop a leaning back posture to counteract these changes, so it is essential that correct posture is coached throughout the swim sessions to increase her body awareness. Encouraging the mother to lift the growing baby up and into the pelvis will develop her awareness of correct alignment.
The cardiovascular system
During pregnancy the volumе of blood we pump around the body actually increases, so the hear has to work harder. It therefore adapts and becomes stronger to cope with the demand. Pre-exercise heart rate will be slightly higher during pregnancy due to the increased blood volume and circulatory demands.
High intensity activities may restrict blood flow to the fetus: they should be avoided during pregnancy. It is also wise to exercise for a shorter duration because foetal heart rate may increase if exercise is too prolonged and too intense. Care must also be taken to avoid excessive rises in temperature, which are dangerous to the fetus in the early stages.
What are the benefits of exercising during pregnancy?
- Decreased aches and pains
- Assistance with weight management
- Easing of constipation
- Improved sleep
- Improved posture
- Improved self-esteem
- Fewer backaches
- Decreased occurrence of varicose veins
- Regaining shape and figure after birth more quickly.
Why is exercising in water ideal during pregnancy?
Buoyancy will provide support to the whole body. The weight of the growing baby will be supported, as will the weight of the growing breasts, so the mother will feel lighter when exercising in the water. This additional support provides many benefits for the expectant mother. It will:
- promote relaxation and the release of tension from the muscles that normally have to work to carry the additional body weight
- ease movement through a fuller range of motion without placing the joints under stress
- reduce the weight and stress placed on the pelvic floor muslces
- reduce compression of the joints
- decrease the impact from jumping movements. Therefore, some of the lower intensity cardiovascular exercise can be performed without placing the body at risk
- reduce the stress placed on the pelvic girdle if raking the weight on the one leg
- reduce the stress on the spine during bending and rotating and hip circling movements. ( Note: care should still be taken not to exceed a comfortable range of motion, even though this area is more supported. A correct pelvic tilt should also be encouraged.)
Resistance provides sufficient intensity to challenge the muscles and maintain their tone without overworking them. It also reduces the speed of movements, so it is more difficult to exceed a comfortable range of motion.
Hydro-static pressure improves the circulation of blood. It may help to prevent an accumulation of harmful wast products that can potentially cause distress to the fetus.
The temperature of the water will have a cooling effect on the body, preventing the body from overheating, something that can be harmful to the fetus. Ensure that rhythmical movements are maintained throughot the session, however, to prevent excessive cooling.
What are the safety considerations?
It is always advisable to check with a doctor or midwife befor starting or continuing an exercise programme when pregnant. Care must be taken to ensure that over-extension does not occur:the mother should listen to her body and do only what feels comfortable.
In general, during the initial stages of pregnancy, fewer changes will need to be made to the programme for a regular exerciser. However, more precautions will need to be taken during the middle and later stages of pregnancy. In all instances the emphasis should be on maintaining fitness rather than improving fitness while pregnant.
How should the session be structured.
The session should include a warm-up and warm-down. It should aim to maintain rather than develop swimming abilities, so it should contain activities to increase general mobility and improve body awareness. A greater emphasis should be placed on breathing, correct posture and alignment. The duration of the session should be shorter and the intensity much lower.
Adaptations to session structure for an ante- and post-natal group
- Emphasis correct posture at the start of, and throughout, the session
- Make movements slower and more controlled
- Increase the number of mobility exercises
- Move all the joints through all possible ranges of motion to reduce stiffness
- Use full range of motion mobility exercises to warm the muscles
- Pulse-raising exercises should be of a much lower intensity, the primary aim being to warm the muscles rather than increase the heart rate
- The intensity of movements should be built up much more gradually to avoid sudden increases in blood pressure
- Directional changes houl dbe minimal to assist maintennace of balance
- Fewer stretches may be needed, especially if full range of motion mobility exercises are included
- Stretch positions should be supported, and care should be taken tnot to exceed a comfortable range of motion
- The pool wall should be used to assist balance.
- Work at a much lower intensity for a modate duration. AIm for slight breathlessness
- Decrease the number of directional movements; centre of gravity changes making it difficult to balance
- More gradual build-up of intensity to avoid increase in blood pressure
- Fewer jumping moves, to maintain comfort for lager breasts
- Avoid explosive movement that lift the body out of the water
- Use lower impact, rhythmical and free-flowing movements
- Use slower movements and music
- Use simple and less co-originated movement patterns
- Promote full range of motion exercises.
Muscular strength and endurance
- Include exercise for the pelvic floor muscles
- No abdominal exercises – be sensitive to amount of fixation of abdominals in water and plan rests
- Select comfortable starting positions
- Avoid exercises that may place excessive pressure on the pelvic girdle
- Use movements related to everyday actions
- Perform fewer repetitions
- Use slower and less intense exercise.
- Include range of motion mobility work to maintain a comfortable temperature
- Include specific relaxation work (if water temperature allows)
- Avoid positions that may overstretch the ligaments
- Select balanced and comfortable positions for passive stretching
- Don’t hold stretches too long, to maintain rather than develop flexibility.
Credit: Debbie Lawrence “EXERCISE IN WATER”
The term ‘buoyancy’ and ‘flotation’ are regularly used interchangeably and this is often not accurate. Flotation is one of the most important initial skills a beginner swimmer must be thought. It is the ability to maintain as much of the body as possible on or near the surface of the water.
Flotation is achieved through the water pushing upwards on the body. This force is known as buoyant force. Buoyant force comes about because the body displaces (moves) water in order to be in it. Therefore, buoyancy is concerned is concerned with the force on the body, and flotation relates to the learner’s ability to use that force.
About 2300 years ago, Archimedes, a Greek scientist, observed that when he sat in his bath in the water level rose and he felt lighter. From these initial observations Archimedes’ principle was born. Archimedes’ principle states that an object that is immersed in the water (either partiality or wholly) experiences and upwards force as the water tries to stop the object from sinking. This buoyant force tends to counteract the effects of gravity and the weight of the object. This results in the weight of the object being reduced by the upward force of buoyancy. The amount of water displaced dictates the amount of buoyant force the body will experience.
The bigger the body, the greater the amount of moved or displaced water and the greater the buoyant force upon it.
Beginner swimmers should be encouraged to experiment with buoyant force. This experimentation could take the form of submerging balls and balloons filled with air or trying to sit on the floor of the pool to experience the upward push of the water. Through experimentation, learners’ understanding and confidence will increase.
Density is the relationship between an object’s mass and its volume. In swimming, water density is thought of primarily in terms of its effect o n buoyancy. Water provides a buoyant force, but it also provides resistance to a student’s propulsion. Of particular interest to instructors is how the human body maximizes the effect of naturally occurring forces of water.
The term ‘specific density’ refers to the difference between the density of an object and the density of pure water.
Pure water density is used as a reference point, having a specific density of 1.0. (This means that each litre of pure water has a mass of 1 kg.) Therefore, anything place in water will float or sink according to its specific density value. Anything with a specific density greater that 1.0 will sink and anything less that 1.0 will float.
The density of the human body varies according to:
- the volume of air in the lungs;
- the amount of fat in the body;
- the degree of muscular development;
- the bone density of the individual.
If a beginner swimmer’s body contains a large amount of fat, which has relatively low specific density, approximately 0.9, the the body is more likely to float. However, a very muscular, lean body, or a body that has a high bone density, is likely to sink. This occurs because both muscle and bone have specific density of greater than 1.0.
In general, women float better that men because they have a higher percentage of body fat. Children generally float better than adults as their torso and lungs make up a greater percentage of their total body mass.
It is often said that humans float better in salt water thatn in fresh water and this is correct. Salt water has a specific density of 1.03 and consequently will push up on the body with more force than fresh water.
Since individual differences will impact upon a beginner swimmer’s ability to float, instructors need to be aware of the variation in density within each swimmer. Body shape, symmetry and breathing all affect the body’s density.
My name is Hristo Milkov. I am 72 years old. My video is set for Butterfly in the sea because I can swim it. Can you?
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