Differential impact of endurance, strength, or combined training on quality of life and plasma serotonin in healthy older women

Neuromodulatory Contribution to Muscle Force Production after Short-Term Unloading and Active Recovery

PURPOSE

Prior evidence has shown that neural factors contribute to the loss of muscle force after skeletal muscle disuse. However, little is known about the specific neural mechanisms altered by disuse. Persistent inward current (PIC) is an intrinsic property of motoneurons responsible for prolonging and amplifying the synaptic input, proportionally to the level of neuromodulation, thus influencing motoneuron discharge rate and force production. Here, we hypothesized that short-term unilateral lower limb suspension (ULLS) would reduce the neuromodulatory input associated with PIC, contributing to the reduction of force generation capacity. In addition, we tested whether physical exercise would restore the force generation capacity by reestablishing the initial level of neuromodulatory input.

METHODS

In 12 young adults, we assessed maximal voluntary contraction pre- and post-10 d of ULLS and after 21 d of active recovery (AR) based on resistance exercise. PIC was estimated from high-density surface electromyograms of the vastus lateralis muscle as the delta frequency (Δ F ) of paired motor units calculated during isometric ramped contractions.

RESULTS

The values of Δ F were reduced after 10 d of ULLS (-33%, P < 0.001), but were fully reestablished after the AR (+29.4%, P < 0.001). The changes in estimated PIC values were correlated ( r = 0.63, P = 0.004) with the reduction in maximal voluntary contraction after ULLS (-29%, P = 0.002) and its recovery after the AR (+28.5%, P = 0.003).

CONCLUSIONS

Our findings suggest that PIC estimates are reduced by muscle disuse and may contribute to the loss of force production and its recovery with exercise. Overall, this is the first study demonstrating that, in addition to peripheral neuromuscular changes, central neuromodulation is a major contributor to the loss of force generation capacity after disuse, and can be recovered after resistance exercise.

Association between muscle strength and depression in a cohort of young adults

BACKGROUND

The study investigated the association between knee joint muscle strength and the prevalence of depression in a cohort of young adults.

METHODS

The observational, population-based study was performed with 909 participants (29.02 ± 2.03 years; 48.73% male) from the Central European Longitudinal Studies of Parents and Children: Young Adults (CELSPAC: YA), who were retained to analysis. Quadriceps and hamstring knee muscle strength were assessed by isokinetic dynamometry, and depression by Beck's Depression Inventory (BDI-II). Statistical comparisons (Mann-Whitney and Chi-squared test) and effect size analyses (Eta-Squared, and Odds Ratio) were conducted.

RESULTS

The main findings revealed an inverse association between knee joint muscle strength and depression, with individuals who had low muscle strength having 3.15 (95% CI = 2.74-3.62) times higher odds of experiencing depression. Specifically, participants with low extensor strength had 4.63 (95% CI = 2.20-9.74) times higher odds, and those with low flexor strength had 2.68 (95% CI = 1.47-4.89) times higher odds of experiencing depression compared to those individuals with high muscle strength. Furthermore, gender-specific analyses revealed that males with low muscle strength had 2.51 (95% CI = 1.53-4.14) times higher odds, while females had 3.46 (95% CI = 2.93-4.08) times higher odds of experiencing depression compared to individuals with high muscle strength.

CONCLUSIONS

Strong knee muscles seems to be a key factor in preventing depression, specially in female young adults. The results support the importance of promoting an increase in muscle strength through physical activity as a preventive strategy against depression in this population.

Biomolecular Effects of Dance and Dance/Movement Therapy: A Review

The positive health impacts of dance and dance/movement therapy can be seen all the way down to the molecular level. This narrative-style review illustrates this connection by presenting a collection of clinical and preclinical studies that evaluate the effects of dance activities on hormones and other small-molecule metabolites within the human body. The results of these studies show that dance activities can increase levels of nitric oxide, serotonin, estrogen hormones, and HDL cholesterol, while they can decrease levels of dopamine, serum glucose, serum triglycerides, and LDL cholesterol. Levels of cortisol can either be increased or decreased, depending on the type of dance. Many of these results parallel the biomolecular effects of traditional (non-dance) exercise activities, although some contrasting results can also be seen. The concentrations of these molecules and their distributions throughout the body impact health and a wide variety of disease states. This connection to the molecular level provides a perspective for understanding how it is that dance activities are able to affect larger-scale physiological and psychological responses and lead to the positive health outcomes that are observed in many situations.

The positive impact of 12 weeks of dance and balance training on the circulating amyloid precursor protein and serotonin concentration as well as physical and cognitive abilities in elderly women

BACKGROUND

The study aimed to compare the effectiveness of 12-weeks dance training with balance training on fall risk, physical and cognitive functions. The study's second aim was to evaluate the association between physical and cognitive functions with circulating markers of neurodegeneration and cognitive impairments in elders.

MATERIALS AND METHODS

30 older women (aged 73.3 ± 4.5) were randomly assigned into three groups: balance training (BG), dance training (DG) and control group (CG). To assess the study aims Time up and go test (TUG), 6 minute walk test (6MWT), determination test (DT), blood amyloid precursor protein (APP) and serotonin concentration were performed.

RESULTS

The results showed an improvement in 6MWT (p = 0.0001 for DG and BD), walking speed (p = 0.0001 for DG and BG) and TUG, only for DG (p = 0.0013). The number of correct responses in DT increased in both groups (p = 0.014 and p = 0.005, for DG and BG, respectively). In DG the increase in the total number of reactions was observed (p = 0.013). The improvement in cognitive and physical functions was associated with an increase in APP (p = 0.036 and p = 0.014) and a decrease in serotonin concentrations (p = 0.042 and p = 0.049), respectively in DG and BG.

CONCLUSION

Dance training intervention could have more benefits on elders' physical and cognitive functions. However, both trainings may be important factors modifying the concentration of circulating proteins associated with neurodegenerative and cognitive disorders.

The effect of daily life activities on intraocular pressure related variations in open-angle glaucoma

The recent advent of continuous intraocular pressure (IOP) telemetry has led to an increased awareness of the importance of IOP fluctuations, and theories have emerged that IOP variations could play as much a role in glaucoma progression as the mean level of IOP. The aim of the present study was to evaluate the direct effect of common daily activities on IOP-related profiles. Primary open-angle glaucoma and glaucoma suspect patients were prospectively enrolled from specialist clinics at the University of California San Diego (UCSD), USA. Patients were fitted with a SENSIMED Triggerfish (TF) contact lens sensor (CLS) and were instructed to return to their usual daily activities for 24 h. They were asked to record each specific activity or event in a diary. The protocol was repeated twice. The following events were recorded: "walking/cycling", "resistance training", "yoga/meditation", and "emotional stress". CLS measurements recorded 60-to-30 min prior to each event were used as a baseline reference, and all IOP-related fluctuations for 120 min after the start of each event were reported in relation to this reference. Forty relevant events from 22 CLS recordings in 14 patients were retrieved from the diaries. Walking/cycling (n = 10) caused a small but statistically significant elevation of the IOP-related profile during the activity (p = 0.018). Resistance training (n = 11) caused a persistent elevation of the IOP-related profile from the onset of the activity (p = 0.005) through 120 min after the activity was stopped (p = 0.007). Yoga/meditation (n = 4) caused a sustained drop in the IOP-related profiles through to 120 min, although this was not statistically significant (p > 0.380). Emotional stress (n = 13) was associated with a gradual elevation of the IOP-related profile from the start of the stressful stimulus. Both early and late variations were statistically significant (p = 0.038 and p = 0.021, respectively). The present study suggests that emotional stress and resistance training may be associated with persistent IOP-related profile elevation.

Comparison of Periodization Models of Concurrent Training in Recreationally Active Postmenopausal Women

Medeiros, LHL, Sandbakk, SB, Bertazone, TMA, and Bueno Júnior, CR. Comparison of periodization models of concurrent training in recreationally active postmenopausal women. J Strength Cond Res XX(X): 000-000, 2020-Although concurrent training is the most effective way to improve both neuromuscular and cardiorespiratory functions in older populations, there are no studies in the literature comparing different periodization models on cardiorespiratory and muscle strength adaptations. Thus, the main objective of this study was to investigate the effects of different periodization models of concurrent aerobic and strength training using equalized training volume programs on muscle strength and cardiorespiratory fitness in recreationally active postmenopausal women. After 3 weeks of adaptation, 58 women aged 50-75 years were randomly assigned to (a) nonperiodization (NP), (b) daily nonlinear periodization (NLP), or (c) flexible daily NLP (FNLP). At baseline and after 12 weeks, aerobic fitness (peak oxygen uptake [V[Combining Dot Above]O2peak] and the 6-minute walk test) and maximal muscle strength (1 repetition maximum of bench press and leg press) were measured. It was shown that maximal strength increased in the bench press (effect size [ES] 1.18 in NLP and 1.22 in FNLP) and leg press (ES 0.92 in NLP and 0.89 in FNLP) in the periodized groups-in the NP group, these values were 0.49 and 0.46, respectively. In the 6-minute walk test, aerobic fitness statistically improved in all groups-with an ES of 1.02 in the NP, 1.33 in the NLP, and 0.54 in the FNLP. This study showed that only periodization models (NLP and FNLP) induced a moderate ES in maximal strength, and all groups (NP, NLP, and FNLP) demonstrated improved aerobic fitness evaluated by V[Combining Dot Above]O2peak and the 6-minute walk test in recreationally active postmenopausal women.