February 2025
February 2025The Gut-Brain Axis Concept and Frailty
The concept of the gut microbiome has taken the healthcare and fitness world by storm. The biome is affected by lifestyle, including medications, diseases, diet, and exercise. It is thought to effect not just the body but the brain, and cognition in the elderly.
Sarcopenia – the loss of muscle mass and strength with aging – causes disability and frailty. Yet such measures as protein supplementation (now recommended at 1.2-1.6 grams/kg of body weight for those over 60) don’t provide the anabolic effects in the muscles of the elderly as would be expected. Could this be due to the role of the gut microbiome? And does this intersect with cognitive changes in the elderly, too?
A novel twins study of 36 pairs of twins over 60 years of age had one take prebiotics daily while the other took a placebo. Both groups did supervised resistance training (RT) and consumed branched-chain amino acid protein supplements daily. In sufficient amounts, other studies have demonstrated a protective effect against sarcopenia; in fact, RT + protein supplements significantly improve older people’s whole body protein synthesis.
The main conclusions were that “prebiotics changed gut microbiome taxa, [but that there was] no significant difference in muscle function (5-repetition chair raise time; grip strength; Short Physical Performance Battery; International Physical Activity Questionnaire [IPAQ] MET minutes)”.
Oddly, though, “prebiotics were associated with an improvement in the cognitive first-factor score compared with placebo.” In other words, maintaining a healthy gut microbiome may not build your muscles but might build your brain function as you age.
JBJS Oct. 2024
Good Drugs Have Off-Label Impacts
Hypogonadism – otherwise known as low testosterone – in older men is usually treated with testosterone supplementation (TS) to help maintain or build muscle mass. A sub-trial in the TRAVERSE trial aimed to determine whether TS prevented fractures in men with mild hypogonadism. Over 5000 men with hypogonadism or sub-cancer PSA levels were divided into two groups – a TS and a placebo group – for over 3 years. Osteoporosis was not a criterion to be in the study.
More fractures occurred in the TS group (3.5%) vs the controls (2.46%). “There was no difference in the incidence of typical osteoporotic fractures” but there were more ankle and rib fractures among those receiving TS. Why?
The authors conjectured that those types of injuries, typically associated with trauma and/or riskier physical activities, might be the result of older men on testosterone behaving like younger men with plenty of testosterone. And I quote: “Divergent behavioral trajectories between the groups, with testosterone likely causing engagement in activities with greater fracture risk, likely accounted for these findings.”
In other words, testosterone, whether endogenous (made by the body) or exogenous (from outside the body), has a youthful influence, not just on the body but the mind. The authors conclude that researchers should be “assessing the behavioral effects of testosterone in future studies.” Or, watch out for off-label impacts from otherwise on-label drugs.
JBJS Oct. 2024
Tid Bits
Kids heal fast but a traumatic knee injury takes a toll even 2 years later. In a study that compared quadriceps and hamstrings strength every 6 months after either an ACL or non-ACL injury, it was found that strength differences were highest over the first 6 months, plateaued at 12 months, and persisted up to 24 months post-injury. The “average (24 month) residual deficit was similar” in both knee muscle groups and for both boys and girls: ~10-11%. JOSPT Dec. 2024
Chronic ankle instability (CAI) resulting from a ligament sprain can take years to recover from even after initial healing and therapy gets you back in the game. A meta-analysis of studies comparing various physical therapies found that a “a regimen combining balance and strengthening exercises, augmented with either manual therapy or dry needling, was identified as the most effective in enhancing function” and pain relief. And “Tai Chi emerged as the most promising intervention for improving stability”. Multimodal exercises improved ankle range of motion. Ultimately, PT works! JOSPT Dec. 2024
One aspect of obesity rarely gets mentioned in mainstream press: the decline of muscle quality due to systemic inflammation, making it harder for obese people to garner the full benefits of resistance training (RT). A 12-wk study of 60 overweight and obese subjects (ages 27-35) had some doing RT 3/wk for just the upper body (UB), or lower body (LB), or combined (UB+LB). Inflammatory markers, fat mass (FM), % body fat (%BF), skeletal muscle mass (SMM), and fat-free mass (FFM) were measured pre- and post. “SMM, FFM, UB and LB strength and power, and [muscle and fat stimulating hormones] significantly increased while FM, %BF, myostatin [a muscle mass blocker], [inflammatory markers] significantly reduced from pre- to post-training in all training groups”. Chalk one up for RT! MSSE Nov. 2024
