ECSS Paris 2023: OP-PN39
INTRODUCTION: Alzheimer’s disease (AD) is the leading cause of dementia in older adults and is characterized by progressive cognitive decline, memory impairment, and neuronal dysfunction. Resistance exercise (RE) supports brain and muscle health by improving cognitive function and protecting against age-related sarcopenia. However, the long-term effects of RE in AD brain and skeletal muscle remain unknown, particularly when initiated early in life and before symptom onset. Here, we investigated the effects of a long-term RE protocol initiated during the pre-symptomatic stage in APP/PS1 mice, an established model of AD, assessing behavioral outcomes, amyloid pathology and neurogenesis in the hippocampus, and oxidative stress markers in skeletal muscle. METHODS: Two-month-old male APP/PS1 and wild-type (WT) mice were assigned to four groups: WT sedentary (WT-SED; n=12), WT resistance exercise (WT-RE; n=10), APP/PS1 sedentary (AD-SED; n=11), and APP/PS1 resistance exercise (AD-RE; n=11). Trained groups performed 26 consecutive weeks (6 months) of RE using a ladder-climbing paradigm with increasing progressive load. At the end of the RE program, mice underwent behavioral testing to evaluate locomotor activity, and learning and memory function. Immunohistochemistry was processed for hippocampal analyses to quantify amyloid-β (Aβ) plaque burden (6E10) and neurogenesis in the dentate gyrus (DCX), and oxidative stress markers were assessed in the gastrocnemius muscle. RESULTS: In APP/PS1 mice, RE reduced hyperlocomotion (p<0.001) and rescued spatial learning and memory deficits (p<0.001; p=0.002, respectively), restoring performance to WT levels. RE also maintained dentate gyrus neurogenesis at WT-like levels (p=0.027) and reduced hippocampal Aβ plaque burden (p=0.007). In the gastrocnemius muscle, RE modulated oxidative stress-related markers, reducing protein carbonyls (p=0.007) and hydrogen peroxide levels (p=0.014) while increasing total antioxidant capacity (FRAP; p=0.015) when compared to WT SED. CONCLUSION: Long-term RE initiated before symptom onset produced robust central and peripheral benefits in APP/PS1 mice, improving behavior, enhancing hippocampal neurogenesis, reducing amyloid pathology, and reducing muscle oxidative stress. These findings support RE as a promising non-pharmacological strategy to delay AD-related disease progression and preserve central and peripheral functions.
Read CV Beatriz LongoECSS Paris 2023: OP-PN39
INTRODUCTION: Brain derived neurotrophic factor (BDNF) is a key mediator of exercise induced neuroplasticity and cognitive enhancement (1). Serum (total measurable) and plasma (freely-circulating) BDNF reflect different physiological sources, yet it is unclear whether resistance loading strategies elicit distinct compartment specific responses. Traditional resistance exercise (TRE) increases BDNF, but whether accentuated eccentric loading provides additional neurotrophic or cognitive benefits remains unknown. Accentuated eccentric exercise (AECC), using supramaximal eccentric loads, imposes greater mechanical tension and neural drive than TRE (2) suggesting it may enhance BDNF signaling and executive functions. This study compared the acute effects of TRE (80% 1RM) and AECC (80% concentric, 110% eccentric) on BDNF and Stroop performance in young adults. METHODS: Sixteen healthy, moderately active young male adults completed three protocols in randomized order, at least 7 days apart: control (seated rest), TRE (80% 1RM), and AECC (80% concentric, 110% eccentric). Each exercise session included bench press, leg press, and lat pulldown (4 sets to failure, 2 min rest). Executive functions were assessed using the Stroop test before and 15 min after each protocol. Serum and plasma BDNF were measured at baseline, 5 min, 1 h, and 3 h post protocol using ELISA. Two-way ANOVA and Friedman test with Wilcoxon signed ranks test were performed separately for the Stroop test, serum and plasma BDNF. Statistical significance was set at p<0.05. RESULTS: Serum BDNF increased 5 min after TRE (+30%, p < 0.001) and AECC (+34%, p = 0.013), with no change in control. At 1 h post, serum BDNF declined after TRE (-11%, p = 0.012) but remained stable after AECC compared to 5 min post. At 3 h post, serum BDNF was slightly above baseline in both exercise protocols (p > 0.05). Plasma BDNF increased 5 min post TRE (+126%, p < 0.001), AECC (+127%, p < 0.005), and control (p = 0.049). Only TRE and AECC maintained elevated plasma BDNF at 1 h (TRE: +60%, p = 0.010; AECC: +48%, both p = 0.039), while control returned to baseline. Stroop Word and Color performance improved after all protocols (all p < 0.01), with the largest improvements after AECC (Word: +7%, Color: +10%, both p < 0.001). Executive functions (Color-Word) improved only after exercise (TRE: +10%; AECC +9%; p < 0.001), not control. CONCLUSION: AECC elicited a more sustained BDNF response than TRE, maintaining elevated serum and plasma concentrations up to 1–3 h post exercise. Executive function improved only after exercise, supporting a link between resistance induced BDNF elevation and cognitive enhancement. These findings suggest that eccentric accentuated loading may optimize acute neurotrophic signaling and highlight the value of assessing both serum and plasma BDNF to capture compartment specific kinetics. Further research should examine whether chronic AECC training yields long term neurocognitive benefits. [1] Bathina 2015/ [2] Wagle 2017
Read CV Sara Moškon MaroltECSS Paris 2023: OP-PN39
INTRODUCTION: Human skeletal muscles have adaptive plasticity in response to resistance training, and hypertrophic adaptation requires high energy and protein costs. Recent evidence has shown that hypertrophy of recruited muscles can occur at the expense of non-recruited muscle atrophies under limited energy and protein availability [1], suggesting that these resources are preferentially allocated to recruited muscles. This finding raises a further question: does recruiting multiple muscle groups during whole-body resistance exercise attenuate the hypertrophic response of targeted muscles, potentially due to the distribution of limited nutritional resources across a greater number of recruited muscles? Here, we investigated the hypertrophic responses of targeted muscles (e.g., pectoralis major and triceps brachii) after resistance training programs using multiple exercises (bench press, squat, and stiff-leg deadlift) or a single exercise (bench press only). METHODS: Forty healthy young males were divided into training group performing multiple exercises (ME), training group performing a single exercise (SE), and control group (CON). The ME performed bench press, full squat, and stiff-leg deadlift, whereas SE performed only bench press at 40% of one-repetition maximum (1RM) with 3 sets of 10 repetitions at two weekly sessions for eight weeks. Before and after this period, we assessed 1RM for the bench press, full squat, and stiff-leg deadlift as well as volumes of the pectoralis major, triceps brachii (long head and medial + lateral heads), and individual lower limb muscles. Moreover, energy and protein intakes were monitored using nutrition-tracking apps, whereas basal and activity energy expenditures were estimated using a triaxial accelerometer during the intervention period. The 1RM and volume were analyzed using mixed-effects models (time × group) and analysis of covariance with adjustments for baseline values, dietary intakes, and energy expenditure, and semi-partial correlation analysis. RESULTS: There were increases in 1RM of the bench press and volumes of the pectoralis major and medial and lateral heads of the triceps brachii in SE (all p ≤ 0.001), but not in ME or CON. Moreover, the relative changes in these variables were approximately 2–3 times greater in SE than ME (p = 0.001–0.038) and CON (p = 0.001–0.008). In ME, relative increase in volume of the pectoralis major was associated with the protein intake normalized to body mass (p = 0.017, r = 0.669). CONCLUSION: Multiple resistance exercises attenuate hypertrophic responses of targeted muscles and strength gain compared with a single exercise. Additionally, the attenuation of hypertrophic responses in a preferentially recruited muscle was most pronounced, especially in the participants with limited protein availability. These findings highlight that training multiple muscle groups simultaneously is “not always better” for maximizing muscle hypertrophy and strength gains. Ref. 1. Van vossel et al. Med Sci Sports Exerc (2024)
Read CV Raki KawamaECSS Paris 2023: OP-PN39