Fish-oil supplementation enhances the effects of strength training in elderly women
 
 
Journal Title (Medline/Pubmed accepted abbreviation):  Am. J. Clin. Nutr.
Year: 2012
Volume: 95
Page numbers: 428-436

Summary of background and research design:

Background: Omega–3 fatty acids, which are in high concentrations in fish oil, have been shown to improve the efficiency of signaling in the nervous system and increase heart muscle function in the elderly. The two most bioactive omega–3 fatty acids are eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).

Hypothesis:Fish oil supplementation will increase the effects of a strength training routine on the neuromuscular system in elderly women. Also, increased amount of time taking fish oil supplements will lead to increased benefits of exercise.

Subjects: 45 healthy, Caucasian women, age 64 ± 1.4 y.

Experimental Design: stratified randomization according to knee extension strength, repeated measures. Participants were unaware of the other treatment groups.

Treatments: Fish oil was delivered in capsules to equate to 2 g/day (about 0.4 g EPA and 0.3 g DHA)
ST- No supplement, strength training only ST90– Fish oil
supplementation during the strength training routine (90 days)
ST150– Fish oil supplementation for the 60 days before the strength training routine, then also during the 90 day strength training (150 days total)

Protocol:Neuromuscular and functional capacity of the muscle were assessed at the beginning and the end of the strength training routine. The ST150 group was also assessed for these parameters before the start of taking the supplement. Participants were acquainted with the exercises and repetition maxima were determined in the first 2 wks. Subsequently, the strength training program was performed 3 times per week for 12 weeks. Several lower body exercises using pulley–type machines were performed with the weight adjusted accordingly as their strength progressed. Strength was assessed by peak torque during a maximal voluntary isometric contraction (pushing against an immovable object) for various muscles. Meanwhile, a surface electromyography device evaluated muscle activation. Functional capacity was assessed by evaluating performance at everyday tasks, for example “chair rising” and a 6 min walk.


Summary of research findings:
  • Fish oil supplementation effectively increased circulating EPA and DHA levels in the blood in ST90 and ST150 compared to the control group (ST).
  • Muscle strength increased in all groups as a result of the strength training. Moreover, participants in ST90 and ST150 improved to a greater degree than ST. There were no additional benefits observed in ST150 compared to ST90.
  • Similarly, all participants increased the rate of torque development (RTD), which corresponds to muscle contractility. Those taking fish oil achieved greater improvements
  • Muscle activation, as measured by the electromyography device, was increased in all groups after the training period compared to before training. The supplemented groups showed even greater improvement in several muscles. ST150 exhibited greater muscle activation than ST90 in the gastrocnemius (calf).
  • Another metric of the neuromuscular response is the time it takes between the onset of electromyographic activity and the onset of the mechanical response. This time decreased in all participants, suggesting a more responsive neuromuscular system. The time was decreased even further in those supplemented with fish oil, though there was no difference between ST90 and ST150.
  • There were improvements in the “foot up and go” test, the “chair–rising” test, and the 6 min walk in all groups, with the fish oil groups achieving even greater gains in the latter 2 tests.

Key practice applications: Fish oil supplementation at 2 g/day helped maximize the gains from strength training in these older women by increasing the responsiveness, strength, and function of their neuromuscular system.

Key search terms for this article (5-7 terms):elderly, older, fish oil, omega–3’s, EPA, DHA, strength, cachexia, resistance training, strength training

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