Raising the Bar for Public Health: Resistance Training and Health Benefits

The major benefits of resistance training include four primary areas: cardiovascular, musculoskeletal, neuropsychological, and metabolic. Resistance exercise improves overall cardiovascular health while significantly reducing the risk of associated diseases. Cardiovascular health is specifically enhanced through the lowering of blood pressure as well as improved lipid and inflammatory profiles. Resistance training enhances musculoskeletal health through increases in bone mineral density, tendon and ligament thickness, muscle hypertrophy, and increases in balance and flexibility. Additionally, resistance training provides an effective treatment option for osteoporosis, osteopenia, sarcopenia, arthritis, and low-back pain. Neuropsychologically, resistance exercise reduces anxiety, stress, and depression, while increasing cognitive function in healthy and diseased individuals. Obesity and weight management comprise the primary metabolic focus. Resistance training effectively manages weight and body fat by increasing fat-free mass, resting metabolic rate, and caloric expenditure. Overall, resistance exercise presents an effective treatment option for disease prevention and intervention by improving health and wellness.


INTRODUCTION
Since the inception of structured exercise, aerobic exercise has been touted as the most beneficial and important form of exercise for general health and wellness.This  Sidossis, 2009).With new and emerging research over the past decade, it is evident that another form of exercise is just as important; that is resistance exercise.Resistance training is defined as resisted dynamic or static muscle contraction with varying intensities (Calle & Fernandez, 2010).Recently, numerous associations including the American Heart Association (AHA) and American College of Sports Medicine (ACSM) have added resistance training to their exercise recommendations, right beside aerobic exercise in importance.For this reason, it is important to identify emerging research that has granted this heightened priority to resistance training.Therefore, the present paper serves to elucidate the various benefits and clinical applications of resistance training with a specific focus on the cardiovascular, musculoskeletal, psychological, and metabolic systems.
International Journal of Strength and Conditioning.2023 cause of death both nationally and globally, the cardioprotective attributes of resistance training are of the utmost importance ("Exercise or Physical Activity," 2022).A recent meta-analysis found that resistance training alone confers a 17% risk reduction for cardiovascular disease and all-cause mortality (Momma, Kawakami, Honda, & Sawada, 2022).This benefit is greatly enhanced by its combination with aerobic exercise which grants a 46% and 40% lower risk of cardiovascular disease and all-cause mortality respectively (Momma et al., 2022).Much of the cardioprotective effects of muscle-strengthening exercise are attributed to metabolic, arterial, and cardiac modulation.A recent review linked important cardioprotective effects to an improved inflammatory profile of the heart through mechanisms such as reduction in lipid peroxidation levels, reactive oxygen species, and inflammatory biomarkers (Cezar, Pagan, Damatto, Lima, & Gomes, 2019).Depending on the regimen, resistance-trained individuals have been associated with a 15-45% lower risk for hypertension (M.P. Smith, 2021).A systematic review and meta-analysis from 2016 observed a 4.1 mm Hg reduction in systolic blood pressure (Lemes et al., 2016).This result is significant as a 2 mm Hg reduction in systolic blood pressure can confer around a 10% risk reduction in stroke mortality and a 7% risk reduction in mortality induced by cardiovascular disease (Lewington et al., 2002).
Another important aspect to consider for cardiovascular disease risk is lipid profile.A recent systematic review with meta-analysis found that resistance training promotes reductions in total cholesterol with a medium effect size, in triglycerides with a small effect size, in low-density lipoprotein (LDL) with a medium effect size, and in C-reactive protein levels with a large effect size (Costa et al., 2019).The same study also found that resistance training was associated with increases in highdensity lipoprotein (HDL) with a medium effect size and adiponectin concentrations with a large effect size.Another meta-analysis utilized randomized controlled studies to quantify these improvements in lipid profile.Kelley and Kelley found significant reductions in total cholesterol by -5.5 mg/dl, total cholesterol to HDL ratio by -0.5, non-HDL by -8.7 ml/ dl, LDL by -6.1 mg/dl, and triglycerides by -8.1 mg/ dl (Kelley & Kelley, 2009).By improving lipid profile, blood pressure, and metabolic factors, resistance training is able to provide significant improvements in cardiovascular health.
Even in individuals that do suffer from cardiovascular disease, resistance training is shown in preclinical trials to improve outcomes.Resistance training prior to myocardial infarction was shown to prevent negative changes to aerobic and anaerobic capacity, prevent cardiovascular sympathetic increments, reduce sympathetic tonus to the heart and vessels, and prevent increases in left-ventricular pro-inflammatory cytokine concentrations in one preclinical trial (Barboza et al., 2016).Furthermore, preclinical research demonstrates resistance training following myocardial infarction to be a safe and effective rehabilitation tool given its significant reductions in global cardiac stress and improvements in cardiac and autonomic nervous system functioning (Grans et al., 2014).

MUSCULOSKELETAL
Perhaps the most renowned benefit of resistance training is improvement in musculoskeletal health and function.The most obvious of these benefits concerns skeletal muscle.Resistance training has been shown on numerous accounts to elicit muscle hypertrophy and increase strength, flexibility, and balance thus proving a powerful tool in the treatment of sarcopenia (De Spiegeleer, Petrovic, Boeckxstaens, & Van Den Noortgate, 2016).A recent review paper identified the atrophy of myosin heavy chain (MHC) II fibres as the primary source of age-related decrements in skeletal muscle function (Grosicki, Zepeda, & Sundberg, 2022).This finding is significant as clear evidence now supports that muscle preservation with aging is almost exclusively a fast-twitch fiber problem.Therefore, resistance training is supported as a highly effective solution as it is the most effective exercise modality for eliciting MHC type II fibres hypertrophy and thus attenuating age-related strength and power decline (Grosicki et al., 2022).Through muscular adaptation, resistance training also markedly reduces the overall risk and severity of musculoskeletal injury due to its positive effects on bone mineral density, connective tissue, and muscle mass (Hoffman, 2017).These improvements in bone mineral density then transfer over to its efficacy in the treatment of osteoporosis and osteopenia.A recent meta-analysis analyzed the effect of high-load resistance training on bone mineral density in osteoporotic and osteopenic patients.Kitsuda   This increase in fat-free mass proves significant as energy expenditure is directly linked to fat-free mass and body weight (Health, 1989)

CONCLUSION
While we elucidate the major positive side effects associated with resistance training, there are still numerous other benefits not mentioned here.The cardiovascular, musculoskeletal, neuropsychological, and metabolic systems represent four major areas that resistance exercise is known to significantly benefit.These effects are directly and concisely reflected by the significant improvement in all-cause mortality and quality of life.Not only is resistance training preventative medicine through its reduction in disease risk and enhancement of health and wellness, but it is also an effective intervention through its alleviation of disease signs and symptoms.Overall, the already extensive benefit of resistance exercise will only continue to develop as emerging research elucidates new applications.

Resistance Training Health Benefits
claim is largely due to the plethora of clinical research surrounding aerobic exercise as opposed to other forms and modalities of training (Aguiar, Morgan, Collins, Plotnikoff, & Callister, 2014; Ismail, Keating, Baker, & Johnson, 2012; Mann, Beedie, & Jimenez, 2014; Marzolini, Oh, & Brooks, 2012; Tambalis, Panagiotakos, Kavouras, & (Coelho-Junior et al., 2022).Resistance training was associated with a significant positive effect on cognitive scores, measures of cognitive impairment, and executive functions (Landrigan, Bell, Crowe, Clay, & Mirman, 2020).Resistance training is also an effective treatment option for several neurological and psychological disorders.Progressive resistance training was shown to improve cognitive symptoms of dementia with marked improvement of cognitive function in patients with mild cognitive impairment (Fiatarone Singh et al., 2014).Resistance training also offers an effective treatment modality for the reduction of PTSD symptomology (Rosenbaum, Sherrington, & Tiedemann, 2015).With a prevalence of 8.4% in the U.S., major depressive disorder represents one of the most common psychological disorders among Americans (Schulenberg et al., 2021).Substantial evidence supports the efficacy of resistance training as a valid intervention for reducing adult depressive symptoms (O'Connor, Herring, & Caravalho, 2010).After just 10 weeks of a resistance training program, clinical depression was successfully treated in more than 80% of the elderly group (Singh, Clements, & Fiatarone, 1997).Paired with aerobic activity, 10 weeks of resistance training was shown to confer significant improvements in physical self-concept, fatigue, revitalization, tension, tranquility, positive engagement, and total mood disturbance (Westcott, 2012).The aforementioned International Journal of Strength and Conditioning.2023 Raising the Bar for Public Health: Resistance Training and Health Benefits benefits provide evidence for resistance exercise to be a powerful tool and treatment option for improving psychological health.Recent research has highlighted the efficacy of resistance training as an adjunct treatment for addiction and drug abuse.Resistance training has been shown to significantly increase dopamine and serotonin levels in addicted subjects, helping to restore deficits following drug abuse (Akbarpour, Fathollahi Shoorabeh, Moradpourian, & Mozaffari, 2020; Arazi, Dadvand, & Fard, 2017; Arazi, Damirchi, & Poulab, 2016).Preclinical research demonstrated that resistance exercise significantly decreases the positive reinforcing effects of heroin and cocaine through modulation of mu opioid and dopamine receptors (M. A. Smith et al., 2018; Strickland et al., 2016).Although research on resistance training for treating addiction is still scarce and young, the data that does exist is promising.METABOLISM The final major area of efficacy and clinical application for resistance training lies in weight management and the treatment of obesity.With a prevalence of 42.4% in 2017 -2018 and an estimated 3% increase from 2019 to 2020, obesity is a major public health crisis and was recently labeled a national epidemic in the United States (Cdc, 2022; Tiwari & Balasundaram, 2022).As opposed to other exercise modalities such as aerobic exercise, resistance exercise confers greater efficacy for weight management due to its significant impact on metabolism.By increasing fatfree mass, the individual burns more calories in and outside the gym due to increases in resting metabolic rate.This finding was confirmed by numerous studies demonstrating significant increases in fat-free mass and resting metabolic rate following a resistance training program (Broeder, Burrhus, Svanevik, & Wilmore, 1992; Campbell, Crim, Young, & Evans, 1994; Greer, Sirithienthad, Moffatt, Marcello, & Panton, 2015; Hunter, Wetzstein, Fields, Brown, & Bamman, 2000; Lemmer et al., 2001; Pratley et al., 1994; Van Etten, Westerterp, Verstappen, Boon, & Saris, 1997).On average, a 1.4 kg gain of lean weight and a 1.8 kg loss of fat were conferred by the aforementioned resistance training studies.

Raising the Bar for Public Health: Resistance Training and Health Benefits
(Rica et al., 2018;12)icant increases in bone mineral density of the lumbar spine, femoral neck, and total hip (Kitsuda, Wada, Noma, Osaki, & Hagino, 2021).The unprecedented efficacy of resistance training For comparison, bisphosphonate treatment, which is the standard of care for osteoporosis, was found to increase bone mineral density by 3.5% at the lumbar spine and 1.9% at the femoral neck after two years of treatment while the LIFTMOR study utilized just eight months of resistance training to produce comparable results(Hosking et al., 1998).When considering the musculoskeletal system, it is also important to consider everything in between the bones and muscles.Resistance training is particularly effective in improving connective tissue health, specifically by increasing tendon and ligament thickness (Grzelak, Podgorski, Stefanczyk, Krochmalski, & Domzalski, 2012; Mersmann, Bohm, & Arampatzis, 2017).In professional weightlifters, mean cross-sectional area of the patellar ligament was 37.1% greater than in the control group(Grzelak et al., 2012).These improvements in joint health are particularly evident in the treatment of pathological conditions.In patients with rheumatoid arthritis, resistance training is considered "an important cornerstone of the nonpharmacological treatment"(Häkkinen, 2004).Controlled clinical research has demonstrated the efficacy of resistance training in reducing disease activity and associated pain in patients with rheumatoid arthritis(Strasser et al.,  2011).As for osteoarthritis, resistance training is also effective in improving symptomatology and physical performance (Lange, Vanwanseele, & Fiatarone singh, 2008).One of the most common sources of musculoskeletal pain, and even pain in general, is low back pain.U.S. Nationals Surveys found that low back pain is the most common type of pain reported by patients in the U.S. within a threemonth timeframe with a 26.4% prevalence (Deyo,PSYCHOLOGICAL/NEUROLOGICALAlthough resistance training presents numerous physical benefits, less obvious, yet equally important, are the psychological and neurological benefits.Past research has shown significant improvements in quality of life, anxiety, body image, and stress ratings for strength-trained individuals(Rica et al., 2018; Westcott, 2012).As for cognitive benefits, a recent systematic review and metaanalysis showed that resistance training significantly improved overall cognitive function with a medium effect in healthy and cognitively impaired adults