The Effect of Aspalathus Linearis on Muscle Soreness and Post-exercise Recovery in Young, Physically Inactive Women

Overview

Exercise has been found to exert beneficial effect on overall health. However, it also induces muscle damage at the same time. This then leads to muscle pain, temporary inflammation and reduced muscle function. These symptoms can persist for up to 72 hours after physical exertion and thus have a negative impact on a speedy recovery. Research has previously shown that antioxidants play an important role in muscle recovery after physical exertion. For example, antioxidants are known to have a positive effect on muscle damage and muscle soreness, and they also provide an anti-inflammatory effect. An important group of antioxidants are the flavonoids, which are abundantly present in rooibos (aspalathus linearis) tea. Previous research has shown that rooibos tea has a performance-enhancing effect during physical exertion. Despite these positive findings during physical exertion, the effect of rooibos tea on muscle recovery is not yet well known. Moreover, the effects of antioxidants during and after physical exertion have almost only been studied in men. Therefore, the current study will investigate the effects of rooibos tea on inflammation, muscle damage and muscle pain in a female population, and whether the muscle recovery capacity can ultimately be accelerated.

On volunteers initial visit to the lab, they will be screened to assess their inclusion using the inclusion and exclusion criteria. Those who qualify for the study will be informed of the detailed procedures of the study. If they still decide to participate, they will be asked to read and sign the informed consent form. They will be asked to avoid taking NSAIDS during the course of the study. Participants will also be asked to refrain from the consumption of flavonoid-rich foods, drinks and supplements for 7 days prior to the test day. During the second visit (test day), baseline data such as body composition, anthropometrical variables, inflammatory markers (creatine kinase, TNF-α, IL-1 and IL-6), perceived muscle soreness and recover, and the quadriceps muscle functioning will be measured. The test will be done in the morning between 8:00 and 12:00 noon. To standardize the metabolic state of the participant during the testing sessions they will not be required to eat for at least two hours before testing. Moreover, participants will be required not to take caffeinated drinks and alcohol at least 12 hours before testing and not do any vigorous activities that have a rating of perceived exertion (RPE) more than (\>) 12 on the Borg scale or any unusual exercise at least 24 hours before testing. Participants will perform an 8 min warm-up of brisk walking on a treadmill (4-7 kph). They will then be subjected to the BIODEX exercise protocol. The protocol is composed of two exercise bouts (A and B), each of which comprises of 15 series of 12 maximum intermittent knee extensions conducted using the right leg on an isokinetic dynamometer with a 60 min break in between. During the 60 min break, the participants will cycle at 100 W on a bicycle ergometer (Monark) for 15 min in between bouts A and B, and then they rested in a semi-supine position for the next 45 min until bout B began. After completion of the exercise protocol, each participant will be asked to step down a total of four times from a bench 30.45 cm (1 ft.) high, alternating the leading leg between attempts to have each leg lead twice to assess the perceived muscle soreness using a 100-point visual analogue scale (VAS). Participants will then be randomised into two (2) groups; the Aspalathus linearis group (AG) and the control group (CG). Participants will be asked to return after 24, 48 and 72 hours of the exercise. During each visit, the baseline measurements, perceived muscle soreness and muscle recovery will be repeated.