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Luder G.1, Kraehenbuehl M.M.2, Liechti M.N.2
1Bern University Hospital, Department of Physiotherapy, Berne, Switzerland, 2Bern University of Applied Sciences, Health, Discipline Physiotherapy, Berne, Switzerland
Background: Resistance training (RT) is frequently used as treatment in physical therapy, e.g. in persons with osteoarthritis of the knee or hip, for patients with low back pain or after orthopedic surgery. In general the aims are gains in strength and muscle mass, as well as improvements in functional movements and better performance of daily life activities. Usually in the recommendations no difference is made between women and men. However, there are important differences in terms of muscle mass and body composition, in hormone levels and hormonal changes, as well as in psychological factors. Thus it might be important to know differences in the response to RT between women and men for the individual adaptation of prescription and instruction during physical therapy.
Purpose: The aim of this review was to identify influencing factors on gain in strength and muscle mass by resistance training in healthy women and to compare women and men in terms of these gains.
Methods: A systematic literature search was performed in PubMed, CINAHL, Embase and SPORTDiscus for studies between January 2000 and April 2016. Included were studies investigating strength or resistance training of at least six weeks in women between 18- 40 years, which included only women or compared women and men as separate groups. Study quality was rated with the Cochrane risk of bias tool.
Results: Totally 174 studies were screened and finally 13 studies were included in the review. All studies showed high or middle risk of bias, mainly due to lacking of randomization and blinding and because of researching small groups. Eight of the studies looked at influencing factors to the training and five trials were investigating differences between women and men. Factors influencing the response to RT were menstrual cycle, training intensity and duration, as well as type of training. Compared to men, women displayed in general higher relative increase of strength and muscle mass by RT, but lower absolute changes by the training.
Conclusion(s): The evidence level in this field is low, mainly because of the poor quality of the studies. The results of the studies were difficult to compare because of different types of training, different outcome measurements and various duration of the training period. Influencing factors were rarely reported separately for women and men, except for menstrual cycle. No studies were found looking at motivation and other psychological factors. In general, there are differences between women and men in the response to RT. The higher relative increases may reflect the lower starting level of the women.
Implications: No clear recommendation can be given at this time, based on the actual studies concerning influencing factors. Differences in absolute and relative strength gain must be considered when performing and assessing RT with women. More research is needed concerning influencing factors in women doing RT, i.e. the monthly hormonal changes, best type and duration of training and also motivational factors.
Funding acknowledgements: No external financial support was given for this study.
Topic: Musculoskeletal
Ethics approval: No ethical approval was necessary for this review of the literature.
All authors, affiliations and abstracts have been published as submitted.
