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Resistance training program of the young and older experimental groups (performed with resistance machines).*
Source publication
The present study investigated whether differences in neuromuscular performance and muscle hypertrophy occur between young and older men. Twenty-three young (29 ± 9 yr) and 26 older men (64 ± 8 yr) completed 10 weeks of high volume, medium load "hypertrophic" resistance training with low frequency (twice per week) with 10 young (34 ± 11 yr) and 11...
Context in source publication
Context 1
... was performed by both young and older men twice per week for a total of 10 weeks with at least 2 days between sessions, and all major muscle groups were performed in 1 training session (Table 2). Briefly, leg exercises (bilateral leg press, knee extension, and knee flexion) were performed before upper-body and torso exercises; bench press, pull- down, shoulder press, seated row, triceps pushdown, biceps curl, abdominal crunches, and back raises. ...
Similar publications
From the several methodological prescription variables manipulations possibilities originated the various strength training (ST) methods or systems. The propose of the present study was to review the literature of original studies that analyzed the ST methods and systems, their methodologies and practical applications. Based on the analysis of 20 o...
Background
Resistance exercise (RE) improves neuromuscular function and physical performance after stroke. Yet, the effects of RE emphasizing eccentric (ECC; lengthening) actions on muscle hypertrophy and cognitive function in stroke patients are currently unknown. Thus, this study explored the effects of ECC-overload RE training on skeletal muscle...
Citations
... The observed differences in 1-RM and MVC between young and older adults would be expected due to the agerelated reduction in maximal strength (Bemben et al. 1991). Further, both young and older adults responded positively to a short-term strength training intervention observed through increases in 1-RM and MVC, again as expected from previous studies (Christie and Kamen 2014;Häkkinen et al. 2000;Walker and Häkkinen 2014). The 1-RM increases in the present study of Δ14% and Δ9% in young and older adults, respectively, are similar to those reported by Walker and Häkkinen (2014) over ten weeks of training. ...
... Further, both young and older adults responded positively to a short-term strength training intervention observed through increases in 1-RM and MVC, again as expected from previous studies (Christie and Kamen 2014;Häkkinen et al. 2000;Walker and Häkkinen 2014). The 1-RM increases in the present study of Δ14% and Δ9% in young and older adults, respectively, are similar to those reported by Walker and Häkkinen (2014) over ten weeks of training. Interestingly, increases in lean leg mass in that study occurred only in the younger group (Walker et al. 2014), and only the young group increased skeletal muscles mass in the present study. ...
... The 1-RM increases in the present study of Δ14% and Δ9% in young and older adults, respectively, are similar to those reported by Walker and Häkkinen (2014) over ten weeks of training. Interestingly, increases in lean leg mass in that study occurred only in the younger group (Walker et al. 2014), and only the young group increased skeletal muscles mass in the present study. These converging results suggest that neural mechanisms, rather than morphologic, may be responsible for increased maximal strength in previously untrained older adults when initiating strength training. ...
Introduction
Strength training mitigates the age-related decline in strength and muscle activation but limited evidence exists on specific motor pathway adaptations.
Methods
Eleven young (22–34 years) and ten older (66–80 years) adults underwent five testing sessions where lumbar-evoked potentials (LEPs) and motor-evoked potentials (MEPs) were measured during 20 and 60% of maximum voluntary contraction (MVC). Ten stimulations, randomly delivered, targeted 25% of maximum compound action potential for LEPs and 120, 140, and 160% of active motor threshold (aMT) for MEPs. The 7-week whole-body resistance training intervention included five exercises, e.g., knee extension (5 sets) and leg press (3 sets), performed twice weekly and was followed by 4 weeks of detraining.
Results
Young had higher MVC (~ 63 N·m, p = 0.006), 1-RM (~ 50 kg, p = 0.002), and lower aMT (~ 9%, p = 0.030) than older adults at baseline. Young increased 1-RM (+ 18 kg, p < 0.001), skeletal muscle mass (SMM) (+ 0.9 kg, p = 0.009), and LEP amplitude (+ 0.174, p < 0.001) during 20% MVC. Older adults increased MVC (+ 13 N·m, p = 0.014), however, they experienced decreased LEP amplitude (− 0.241, p < 0.001) during 20% MVC and MEP amplitude reductions at 120% (− 0.157, p = 0.034), 140% (− 0.196, p = 0.026), and 160% (− 0.210, p = 0.006) aMT during 60% MVC trials. After detraining, young and older adults decreased 1-RM, while young adults decreased SMM.
Conclusion
Higher aMT and MEP amplitude in older adults were concomitant with lower baseline strength. Training increased strength in both groups, but divergent modifications in cortico-spinal activity occurred. Results suggest that the primary locus of adaptation occurs at the spinal level.
... Against the primary hypothesis, no loss in leg lean mass was observed in the present study as assessed by through DXA scanning. The method is valid (e.g., Cameron et al. 2020) and reliable (~ 1% CV%, Sillanpää et al. 2014;Walker and Häkkinen 2014) for this purpose, and it has identified lean mass/fat-free mass from step-reduction previously (Arentson-Lantz et al. 2019;Breen et al. 2013). However, the present study is not alone in observing maintained LLM after step-reduction (McGlory et al. 2018). ...
Purpose
This study determined the effects of a 2-week step-reduction period followed by 4-week exercise rehabilitation on physical function, body composition, and metabolic health in 70–80-year-olds asymptomatic for injury/illness.
Methods
A parallel-group randomized controlled trial (ENDURE-study, NCT04997447) was used, where 66 older adults (79% female) were randomized to either intervention or control group. The intervention group reduced daily steps to < 2000, monitored by accelerometer, for two weeks (Period I) and then step-reduction requirement was removed with an additional exercise rehabilitation 4 times per week for 4 weeks (Period II). The control group continued their habitual physical activity throughout with no additional exercise intervention. Laboratory tests were performed at baseline, after Period I and Period II. The primary outcome measure was leg lean mass (LLM). Secondary outcomes included total lean and fat mass, blood glucose and insulin concentration, LDL cholesterol and HDL cholesterol concentration, maximal isometric leg press force (MVC), and chair rise and stair climb performance.
Results
LLM remained unchanged in both groups and no changes occurred in physical function nor body composition in the intervention group in Period I. HDL cholesterol concentration reduced after Period I (from 1.62 ± 0.37 to 1.55 ± 0.36 mmol·L⁻¹, P = 0.017) and returned to baseline after Period II (1.66 ± 0.38 mmol·L⁻¹) in the intervention group (Time × Group interaction: P = 0.065). MVC improved after Period II only (Time × Group interaction: P = 0.009, Δ% = 15%, P < 0.001).
Conclusion
Short-term step-reduction in healthy older adults may not be as detrimental to health or physical function as currently thought.
... Furthermore, voluntary activation (VA), an electrophysiological technique assessing neural transmission from the motor cortex to muscles, declines with age (Clark & Taylor, 2011;Harridge et al., 1999;Jakobi & Rice, 2002;Shinohara et al., 2003). However, research on VA improvements post strength-exercise in older and younger adults has produced inconclusive results (Cannon et al., 2007;Walker & Häkkinen, 2014). Additionally, adaptations within the spinal cord that may contribute to increased force production after strength-exercise have been explored using cervicomedullary evoked potentials (CMEPs) in younger adults (Nuzzo et al., 2016). ...
... Considering the limited examination of acute changes in neural drive, our findings in younger adults align somewhat with some studies in the chronic strengthexercise literature that observed no changes in neural drive (Cannon et al., 2007;Harridge et al., 1999;Herbert et al., 1998;Scaglioni et al., 2002, Walker et al., 2013. However, some studies have reported increases in neural drive following training in both younger and older adults (Knight & Kamen, 2001;Walker & Häkkinen, 2014). The mechanism decreasing neural drive in older adults likely emanates from the reduction in MVF obtained post exercise during the CAR calculation. ...
... It is known that in healthy young adults, RT elicits adaptations of several levels of the descending neuroaxis, improving VA. Among the adaptations are increases in net corticospinal excitability, in addition to improved maximal MUDR [19,[35][36][37][38]. Recently, it has been suggested that increased strength following RT in young and older adults may be due to different adaptation mechanisms, being mainly muscular in young adults and mainly neural in older adults [39]. Accordingly, it has been shown previously that older adults display decreased resting excitability for several levels compared to young adults [2,10,40]. ...
... All the identified studies quantified VA but none used parallel measures of corticospinal excitability (e.g., V-waves and TMS). The majority of the studies reported baseline reductions in VA for older adults compared to young adults [39,[69][70][71][72]. However, Knight and co-workers [73] reported that VA was 2% lower for older adults, but not significant (p > 0.05). ...
... However, Knight and co-workers [73] reported that VA was 2% lower for older adults, but not significant (p > 0.05). Conversely, Walker and Häkkinen [39] reported that older adults showed lower VA compared to young adults at baseline (p < 0.05), as did Simoneau and co-workers (p < 0.05) [72]. Similarly, Hvid and co-workers [71] demonstrated that both MVIC and VA were lowered for older adult males compared to young males (p < 0.05). ...
Age-related decline in voluntary force production represents one of the main contributors to the onset of physical disability in older adults and is argued to stem from adverse musculoskeletal alterations and changes along the descending neuroaxis. The neural contribution of the above is possibly indicated by disproportionate losses in voluntary activation (VA) compared to muscle mass. For young adults, resistance training (RT) induces muscular and neural adaptations over several levels of the central nervous system, contributing to increased physical performance. However, less is known about the relative neuroadaptive contribution of RT in older adults. The aim of this review was to outline the current state of the literature regarding where and to what extent neural adaptations occur along the descending neuroaxis in response to RT in older adults. We performed a literature search in PubMed, Google Scholar and Scopus. A total of 63 articles met the primary inclusion criteria and following quality analysis (PEDro) 23 articles were included. Overall, neuroadaptations in older adults seemingly favor top-down adaptations, where the preceding changes of neural drive from superior levels affect the neural output of lower levels, following RT. Moreover, older adults appear more predisposed to neural rather than morphological adaptations compared to young adults, a potentially important implication for the improved maintenance of neuromuscular function during aging.
... For example, strength-training is a simple, cost effective and easily translated intervention to increase force production in most people and is recommended for older adults (Fragala et al., 2019). However, despite several strength-training studies reporting increased VA in older adults, (Knight and Kamen, 2001;Scaglioni et al., 2002;Walker and Häkkinen, 2014), the results are conflicting (Clark and Taylor, 2011) and hence a systematic evaluation of the literature is required to determine consensus. In addition, measuring VA provides limited insight into the specific site and or neural mechanism underpinning maximal force production, thus transcranial magnetic stimulation (TMS) may provide greater insight into the neurological mechanisms underpinning strength gain and strength loss. ...
... Complete strength data were extracted from 20 studies (Bellew, 2002;Beurskens et al., 2015;Caserotti et al., 2008;De Vos et al., 2005;Earles et al., 2001;Gurjão et al., 2012;Henwood and Taaffe, 2005;Hortobagyi et al., 2001;Hvid et al., 2016;Jiang et al., 2016;Judge et al., 1994;Kalapotharakos et al., 2010;Laidlaw et al., 1999;Lixandrao et al., 2016;Lohne-Seiler et al., 2013;Marsh et al., 2009;Tracy et al., 2004;Unhjem et al., 2020;Walker and Häkkinen, 2014;Wolfson et al., 1996) that measured maximum strength post-strength-training in older adults (n = 312) compared to age-matched controls (n = 280). The pooled data indicated that, following strength-training, the older trained group exhibited a moderate increase in strength (25.49%; ...
... Eleven out of 20 studies (Bellew, 2002;Beurskens et al., 2015;Caserotti et al., 2008;Earles et al., 2001;Gurjão et al., 2012;Hortobagyi et al., 2001;Judge et al., 1994;Lixandrao et al., 2016;Tracy et al., 2004;Unhjem et al., 2020;Wolfson et al., 1996) trained the lower-body to assess strength gains whereas only two studies trained the upper-body (Jiang et al., 2016;Laidlaw et al., 1999). The remaining seven studies (De Vos et al., 2005;Henwood and Taaffe, 2005;Hvid et al., 2016;Kalapotharakos et al., 2010;Lohne-Seiler et al., 2013;Marsh et al., 2009;Walker and Häkkinen, 2014) trained both the upper-and lower-body for examination but kept the focus on the lower-body. ...
... For example, strength-training is a simple, cost effective and easily translated intervention to increase force production in most people and is recommended for older adults (Fragala et al., 2019). However, despite several strength-training studies reporting increased VA in older adults, (Knight and Kamen, 2001;Scaglioni et al., 2002;Walker and Häkkinen, 2014), the results are conflicting (Clark and Taylor, 2011) and hence a systematic evaluation of the literature is required to determine consensus. In addition, measuring VA provides limited insight into the specific site and or neural mechanism underpinning maximal force production, thus transcranial magnetic stimulation (TMS) may provide greater insight into the neurological mechanisms underpinning strength gain and strength loss. ...
... Complete strength data were extracted from 20 studies (Bellew, 2002;Beurskens et al., 2015;Caserotti et al., 2008;De Vos et al., 2005;Earles et al., 2001;Gurjão et al., 2012;Henwood and Taaffe, 2005;Hortobagyi et al., 2001;Hvid et al., 2016;Jiang et al., 2016;Judge et al., 1994;Kalapotharakos et al., 2010;Laidlaw et al., 1999;Lixandrao et al., 2016;Lohne-Seiler et al., 2013;Marsh et al., 2009;Tracy et al., 2004;Unhjem et al., 2020;Walker and Häkkinen, 2014;Wolfson et al., 1996) that measured maximum strength post-strength-training in older adults (n = 312) compared to age-matched controls (n = 280). The pooled data indicated that, following strength-training, the older trained group exhibited a moderate increase in strength (25.49%; ...
... Eleven out of 20 studies (Bellew, 2002;Beurskens et al., 2015;Caserotti et al., 2008;Earles et al., 2001;Gurjão et al., 2012;Hortobagyi et al., 2001;Judge et al., 1994;Lixandrao et al., 2016;Tracy et al., 2004;Unhjem et al., 2020;Wolfson et al., 1996) trained the lower-body to assess strength gains whereas only two studies trained the upper-body (Jiang et al., 2016;Laidlaw et al., 1999). The remaining seven studies (De Vos et al., 2005;Henwood and Taaffe, 2005;Hvid et al., 2016;Kalapotharakos et al., 2010;Lohne-Seiler et al., 2013;Marsh et al., 2009;Walker and Häkkinen, 2014) trained both the upper-and lower-body for examination but kept the focus on the lower-body. ...
There are observable decreases in muscle strength as a result of ageing that occur from the age of 40, which is thought to occur as a result of changes within the neuromuscular system. Strength-training in older adults is a suitable intervention that may counteract the age-related loss in force production. The neuromuscular adaptations (i.e., cortical, spinal and muscular) to strength-training in older adults is largely equivocal and a systematic review with meta-analysis will serve to clarify the present circumstances regarding the benefits of strength-training in older adults. 20 studies entered the meta-analysis and were analysed using a random-effects model. A best evidence synthesis that included 36 studies was performed for variables that had insufficient data for meta-analysis. One study entered both. There was strong evidence that strength-training increases maximal force production and rate of force development and muscle activation in older adults. There was limited evidence for strength-training to improve voluntary-activation, the volitional-wave and spinal excitability, but strong evidence for increased muscle mass. The findings suggest that strength-training performed between 2-12 weeks increases strength, rate of force development and muscle activation, which likely improves motoneurone excitability by increased motor unit recruitment and improved discharge rates.
... A 10 MHz linear-array probe (60 mm) coated with water-soluble transmission gel and housed in a custommade convex support was used. CSA measurements were performed using the extended-field-of-view function as previously described (Walker and Häkkinen 2014;Walker et al. 2020), which has been shown to be a valid and repeatable method when assessing muscle CSA changes over time (Ahtiainen et al. 2010). Triceps brachii measurements were taken at the mid-point between the medial epicondyle and the acromion. ...
Purpose
Men and women typically display different neuromuscular characteristics, force–velocity relationships, and differing strength deficit (upper vs. lower body). Thus, it is not clear how previous recommendations for training with velocity-loss resistance training based on data in men will apply to women. This study examined the inter-sex differences in neuromuscular adaptations using 20% and 40% velocity-loss protocols in back squat and bench press exercises.
Methods
The present study employed an 8-week intervention (2 × week) comparing 20% vs. 40% velocity-loss resistance training in the back squat and bench press exercises in young men and women (~ 26 years). Maximum strength (1-RM) and submaximal-load mean propulsive velocity (MPV) for low- and high-velocity lifts in squat and bench press, countermovement jump and vastus lateralis cross-sectional area were measured at pre-, mid-, and post-training. Surface EMG of quadriceps measured muscle activity during performance tests.
Results
All groups increased 1-RM strength in squat and bench press exercises, as well as MPV using submaximal loads and countermovement jump height ( P < 0.05). No statistically significant between-group differences were observed, but higher magnitudes following 40% velocity loss in 1-RM ( g = 0.60) and in low- ( g = 1.42) and high-velocity ( g = 0.98) lifts occurred in women. Training-induced improvements were accompanied by increases in surface EMG amplitude and vastus lateralis cross-sectional area.
Conclusion
Similar increases in strength and power performance were observed in men and women over 8 weeks of velocity-based resistance training. However, some results suggest that strength and power gains favor using 40% rather than 20% velocity loss in women.
... Moreover, decreased activity has been shown to impede the nervous system's capacity to recruit high threshold motor units responsible for high force generation and power, which is also described as explosive strength (Kraemer et al., 2002;Daly, 2017;Bahat et al., 2021). The increased strength accompanying high intensity resistance training, i.e., weight lifting, is attributed to both increased mass of contractile proteins, as well as greater neural drive to the contracting muscle tissue (Walker and Hakkinen, 2014;Ahtiainen et al., 2016). In addition to the neuromuscular plasticity observed in response to alterations in activity, similar plasticity in neuromuscular function and structure naturally occurs throughout the lifespan beginning with, and even preceding, birth, all the way through the latest stages of senescence (Piasecki et al., 2016;Dobrowolny et al., 2021;Wakabayashi, 2021). ...
Muscle unloading results in severe disturbance in neuromuscular function. During juvenile stages of natural development, the neuromuscular system experiences a high degree of plasticity in function and structure. This study aimed to determine whether muscle unloading imposed during juvenile development would elicit more severe disruption in neuromuscular function than when imposed on fully developed, mature neuromuscular systems. Twenty juvenile (3 months old) and 20 mature (8 months old) rats were equally divided into unloaded and control groups yielding a total of four groups (N = 10/each). Following the 2 week intervention period, soleus muscles were surgically extracted and using an ex vivo muscle stimulation and recording system, were examined for neuromuscular function. The unloading protocol was found to have elicited significant (P ≤ 0.05) declines in whole muscle wet weight in both juvenile and mature muscles, but of a similar degree (P = 0.286). Results also showed that juvenile muscles displayed significantly greater decay in peak force due to unloading than mature muscles, such a finding was also made for specific tension or force/muscle mass. When examining neuromuscular efficiency, i.e., function of the neuromuscular junction, it again was noted that juvenile systems were more negatively affected by muscle unloading than mature systems. These results indicate that juvenile neuromuscular systems are more sensitive to the effects of unloading than mature ones, and that the primary locus of this developmental related difference is likely the neuromuscular junction as indicated by age-related differences in neuromuscular transmission efficiency.
... Therefore, a minimal training duration of 12 weeks may be required for the training to reach its full effect due to the nature of adaptation in the aging musculoskeletal system. 46,47 However, since studies with a wide range of training durations (6-26 weeks) have shown positive outcomes, more studies investigating optimal training duration would be useful. Training beyond 12 weeks may not be practical in a physical therapy setting. ...
Falls are a common health issue among older adults. Muscle weakness, limited physical function, and balance impairment have been identified as the modifiable risk factors for falls. The purpose of this review is to analyze current evidence about the efficacy of power training in improving physical function, improving balance, and preventing falls in older adults. We also provide recommendations regarding power training protocols for older adults. This review suggests that power training is effective in reducing several risk factors for falls. Future interdisciplinary studies are needed to provide evidence about how to incorporate power training in a fall prevention program.
... Similar to AET, there appears to be a dose-response relationship regarding RET and health benefits, wherein higher intensities and higher volumes of RET result in greater improvements in strength and mass in OAs (Peterson et al., 2010(Peterson et al., , 2011Steib et al., 2010;Churchward-Venne et al., 2015;Law et al., 2016). Whether the adaptive response to RET is equivalent in both young and old adults is still debatable, as several investigations have reported no difference between age groups (Häkkinen et al., 1998;Roth et al., 2001;Newton et al., 2002;Walker and Häkkinen, 2014), while others have reported a blunted response in OAs (Raue et al., 1985;Lemmer et al., 2000;Macaluso et al., 2000;Martel et al., 2006). Regardless, RET is clearly beneficial for musculoskeletal health, and is likely the most effective strategy for maintaining and/or increasing muscle mass and strength with age (Law et al., 2016) in turn preventing and potentially reversing sarcopenia and delaying loss of independence (Evans, 1996). ...
Optimal health benefits from exercise are achieved by meeting both aerobic and muscle strengthening guidelines, however, most older adults (OAs) do not exercise and the majority of those who do only perform one type of exercise. A pragmatic solution to this problem may be emphasizing a single exercise strategy that maximizes health benefits. The loss of muscle mass and strength at an accelerated rate are hallmarks of aging that, without intervention, eventually lead to physical disability and loss of independence. Additionally, OAs are at risk of developing several chronic diseases. As such, participating in activities that can maintain or increase muscle mass and strength, as well as decrease chronic disease risk, is essential for healthy aging. Unfortunately, there is a widely held belief that adaptations to aerobic and resistance exercise are independent of each other, requiring the participation of both types of exercise to achieve optimal health. However, we argue that this assertion is incorrect, and we discuss crossover adaptations of both aerobic and resistance exercise. Aerobic exercise can increase muscle mass and strength, though not consistently and may be limited to exercise that overloads a particular muscle group, such as stationary bicycling. In contrast, resistance exercise is effective at maintaining muscle health with increasing age, and also has significant effects on cardiovascular disease (CVD) risk factors, type 2 diabetes (T2D), cancer, and mortality. We posit that resistance exercise is the most effective standalone exercise strategy for improving overall health in OAs and should be emphasized in future guidelines.
