Aqua Research Review – Muscular strength in older females
by Kimberley Huff
Title: ‘The Effects of a Twenty-Four-Week Aquatic Training Program on Muscular Strength Performance in Healthy Elderly Women’
Authors: Thomai Tsourlou, Athanasia Benik, Konstantina Dipla, Andreas Zafeiridis, and Spiros Kellis. Department of Physical Education and Sports Sciences, Aristotelian University of Thessaloniki, Greece.
Source: Journal of Strength and Conditioning Research, 20(4), pp811-818, 2006
Many studies have shown the positive effects of regular exercise on the muscular strength, flexibility, and aerobic capacity of older adults. Research also indicates that shallow water exercise is an appropriate mode of exercise for older adults that may be at risk of joint problems, balance problems and other orthopaedic limitations. Some researchers suggest that the resistive effects of the water create muscular tension and energy expenditure beyond that achieved with land-based training programs. The aim of this study was to determine the effects of an aquatic exercise program with a resistance training component on older women.
Purpose of the study
Research studies typically focus on measuring dynamic muscular strength and endurance. The researchers in this study presented the value of isometric strength in terms of maintaining functional independence. Isometric strength is a factor in carrying groceries, maintaining posture and dynamic stability. This study measured the isometric strength of the muscle groups involved in activities of daily living and functional mobility. The researchers also measured other factors that contribute to loss of mobility and risk of falling, including explosive strength, flexibility and agility.
The purpose of this study was to determine the effectiveness of a 24-week aquatic training program that included both aerobic and resistance training components on muscular strength (both isometric and dynamic), flexibility and functional mobility in healthy women over the age of 60.
Subjects and Methods
Twentyfour, healthy women between the ages of 60 and 75 participated in the study. The participants were divided into two groups, an aquatic exercise group and a control group.
The participants did not participate in a regular exercise program prior to the study. The control group was told to avoid any regular exercise during the study. The exercise group participated in a 60-minute water exercise class, three times a week for 24 weeks. The class consisted of a 10-minute warm up, 25 minutes of aerobic exercise; 20 to 25 minutes of resistance training and a 5-minute cool down.
The intensity of the aerobic component progressed to 80 per cent HRM during the 24 weeks. The resistance training component consisted of exercises for the upper and lower extremities using noodles and cuffs respectively. Two sets of 12 to 15 repetitions were performed for each exercise. The pace was initially set at 60BPM and progressed to 120BPM during the 24 weeks.
The results of the study were very favourable towards the effects of water exercise on muscular strength, flexibility and functional mobility.
- The researchers measured isometric strength of the knee extensor muscles (quadriceps) and knee flexors (hamstrings). Isometric strength with knee extension increased by 10.5 per cent and with knee flexion by 13.4 per cent.
- The researchers also measured hand grip strength – a strong predictor of disability in older adults. Grip strength improved by 13 per cent, a very significant finding because, according to the researchers, grip strength typically decreases 20 to 25 per cent after the age of 60.
- Dynamic strength was measured by using a 3RM (repetition maximum) test protocol. Dynamic strength was tested for knee extension, leg press, chest press and lat pull down. Knee extension increased 25.7 per cent; leg press increased 29.5 per cent; chest press increased 25.7 per cent; there was no improvement in latissimus dorsi strength. The researchers suggested that the buoyant forces of the water support the body, thus reducing the involvement of the back muscles to maintain alignment in the water.
- Power was measured by the use of a dynamic jumping protocol. The results showed an increase in lower extremity power of 24.6 per cent.
- The researchers use a timed up and go test to measure power, speed, agility and balance. Results of the timed up and go test increased by 20 per cent.
- Body composition and flexibility were also assessed. There was a 3.4 per cent increase in lean muscle mass and an 11 per cent increase in flexibility.
Applying this to our classes
The results of this study indicate that a properly designed water exercise program may result in increases in both isometric and dynamic muscular strength, flexibility and functional mobility in healthy women over the age of 60. The program included a combination of aerobic exercise and resistance training. The resistance component was designed to provide a high volume (sets x reps) of exercise.
The researchers did compare the results of this study to other studies that were performed for 12 weeks. The shorter duration studies did not have the significant increases that were noted in this 24-week study. Class participants may need to be educated on the chronic adaptations to water exercise that may not be realised until six months of participation, especially when working with older adults. Participants may also benefit from education on the transfer of the gains in strength, power, agility, and balance to activities of daily living.
One very noteworthy statistic from the study was the percentage of participant adherence. This was a very long study (six months) and 90 per cent of the participants attended the scheduled exercise sessions. There were no reported injuries during the study. These were participants that did not exercise on a regular basis and thus would be at risk of injury and/or drop out. The researchers concluded that this type of exercise provides a safe environment that is well tolerated by older women.
Reprinted with permisson from the Aquatic Exercise Association, www.aeawave.com
Kimberly Huff, MS, CSCS
Kimberly is certified by NSCA, ACSM, ACE, and AEA and has experience in fitness and therapy settings. She presents certification review courses for ACSM and AEA and serves on AEA’s Research Council. Kim has been published in several fitness journals and has presented at international conferences. She is currently serving as the co-chair for the AEA Research Committee.