Pregnancy causes numerous changes in the client, including anatomical, metabolic and cardiorespiratory, which ultimately result in physiological changes, similar to the changes that occur during exercise. It has been suggested that pregnancy may develop into a circulatory stress (Almada et al., 2015).
Current recommendations relating to the training of pregnant females can be summarised as the following:
- 1-3 sets of 10-15 repetitions at 50-70% of 1RM
It has been stated by Almada et al., 2015 that this recommendation is very conservative because little to no research has actually reported the acute response of resistance training. The general consensus appears to be that individuals who are pregnant will tolerate resistance training more effectively than cardiovascular training due to lower cardiovascular stress and heat generation.
Furthermore the responses to resistance training in the upper and lower body have been theorised as separate in themselves. Recently Almada et al., 2015 set out to answer the question: “What are the cardiorespiratory responses of pregnant and non-pregnant women while performing resistance exercise for the upper and lower body at 2 different volumes?”
The four sessions that the researchers examined are listed below:
- 1 Set of 15 repetitions on the pec fly deck
- 1 Set of 15 repetitions of bilateral leg extensions
- 3 Sets of 15 repetitions on the pec fly dec
- 3 Sets of 15 repetitions of bilateral leg extensions
All loads were calculated based on 10RM calculations and loads of 50% 1RM where prescribed.
Key results from the study
- Blood pressure was reduced during both single and multiple sets in the pregnant group – believed to be due to decreased peripheral vascular resistance, which is in line with previous research.
- Cardiorespiratory responses including heart rate, systolic blood pressure and diastolic blood pressure where elevated during the lower body exercise sessions for both pregnant and non-pregnant groups. This was believed to be due to the fact that as the amount of muscle mass working increases, so to does the vascular stress.
- Systolic blood pressure showed a correlation between sets performed and an increase. It is believed that there is a compression effect during the concentric phase, compressing arteries resulting in vascular resistance, which would be magnified each set as muscle perfusion reduces.
Take home points from the study
- This study indicated that the cardiorespiratory response of resistance training in these parameters is safe for a pregnant women in her second trimester.
- She can perform both the pec fly and leg extension for 1-3 sets of 15 repetitions at 50-70% 1Rm safely.