Potential of video games for the promotion of neuroadaptation to multifocal intraocular lenses: a narrative review

Multifocal intraocular lenses (IOLs) are currently usually implanted for the treatment of cataracts because they have been proved to be superior to monofocal IOLs with respect to spectacle independence. In turn, they are associated with a higher prevalence of dysphotopsia symptoms that is one of the most common causes of patient dissatisfaction. Neuroadaptation seems to play a major role in the optimal adaptation to multifocal IOLs. In this context, the development of strategies that facilitate the neuroadaptation process to multifocality might be an effective strategy to reduce patients' dissatisfaction. Video games have been proved to be effective for the improvement of visual acuity and for the promotion of neuroplasticity in elderly subjects and other populations with cortical-related visual impairment. This narrative review highlights the physiological potential of video games as a perceptual strategy to improve visual acuity and promote neuroplasticity in patients using multifocal IOLs, although research is still needed to confirm these benefits in this specific population, with only one comparative study to this date providing evidence of them.

Validity of a novel device for real-time analysis of cyclists' drag area

OBJECTIVES

To assess the reliability, validity, and sensitivity of a novel device (Notio Konect™) which is purported to provide a real-time analysis of aerodynamic drag area (CdA) during cycling.

DESIGN

Observational, cross-sectional study.

METHODS

Fifteen trained cyclists rode in an indoor velodrome using three different positions (upright, aero [holding aero bars], and optimized aero [similar to aero, but wearing a time-trial helmet]). They completed six 1-min trials in each position. The CdA was measured with Notio and with two other systems (Track Aero System™ [TAS] and a validated mathematical model).

RESULTS

The CdA measured with Notio showed good reliability (intra-class correlation coefficient [ICC]=0.92, 90% confidence interval [CI]=0.89-0.95). Notio showed an almost perfect relationship with both TAS (ICC=0.99, 90% CI=0.98-0.99) and the mathematical model (ICC=0.99, 90% CI=0.98-0.99). However, the CdA values provided by the former (0.308±0.051m²) were significantly higher (albeit with a trivial effect size [ES]) compared with TAS (0.300±0.051m², p<0.001, ES=0.15) and the mathematical model (0.303±0.051m², p=0.005, ES=0.09). The CdA was higher in the upright than in the aero position with all systems (all p<0.001, ES=1.84-1.89), and higher in the aero than in the optimized aero position when measured with TAS (p=0.033, ES=0.22) or the mathematical model (p=0.024, ES=0.24), but not with Notio (p=0.220, ES=0.19).

CONCLUSIONS

Notio appears to be reliable, strongly correlated to other established systems, and discerns large (upright vs aero) but not small (aero vs optimized aero) variations in riding position. Further research is needed to confirm its validity in outdoor conditions.

Acute Responses to On-Court Repeated-Sprint Training Performed With Blood Flow Restriction Versus Systemic Hypoxia in Elite Badminton Athletes

PURPOSE

Repeated-sprint training (RS) is commonly conducted in normoxia, but its completion with localized (blood-flow restriction [BFR]) or systemic hypoxia has been proven effective for performance enhancement. Yet, few studies have applied these types of RS sessions in racket sports. The authors aimed to determine the acute responses to these types of training in elite badminton players.

METHODS

Eight male elite badminton players participated in this randomized crossover study. They performed 3 on-court RS sessions, each consisting of 3 sets of 10 repetitions of 10-s badminton-specific movements in normoxia (RSN), systemic normobaric hypoxia (RSH, FiO2 = 14%), or with BFR (RS-BFR, 40% arterial occlusion pressure). Performance, perceptual (ie, rating of perceived exertion), and physiological (ie, pulse saturation, muscle oxygenation, blood lactate, creatine kinase, heart-rate variability) responses were measured after each set and up to 48 h postsession.

RESULTS

RS-BFR induced a greater performance impairment (lower distance and accelerations) and a higher local perceived exertion in the legs than RSN and RSH (P < .05), whereas greater overall fatigue was reported with RSH (P < .05). RSH induced a lower saturation (P < .001), but no differences were observed in muscle oxygenation between conditions. No differences in creatine kinase or heart-rate variability were observed at any time point (from baseline up to 48 h after the session).

CONCLUSIONS

RS-BFR-and, to a lower extent, RSH-resulted in impaired performance and a higher perceived strain than RSN. However, these 2 hypoxic methods do not seem to induce a long-lasting (post 24-48 h) physiological stress in elite badminton players.

Physical Exercise in the Oldest Old

Societies are progressively aging, with the oldest old (i.e., those aged >80-85 years) being the most rapidly expanding population segment. However, advanced aging comes at a price, as it is associated with an increased incidence of the so-called age-related conditions, including a greater risk for loss of functional independence. How to combat sarcopenia, frailty, and overall intrinsic capacity decline in the elderly is a major challenge for modern medicine, and exercise appears to be a potential solution. In this article, we first summarize the physiological mechanisms underlying the age-related deterioration in intrinsic capacity, particularly regarding those phenotypes related to functional decline. The main methods available for the physical assessment of the oldest old are then described, and finally the multisystem benefits that exercise (or "exercise mimetics" in those situations in which volitional exercise is not feasible) can provide to this population segment are reviewed. In summary, lifetime physical exercise can help to attenuate the loss of many of the properties affected by aging, especially when the latter is accompanied by an inactive lifestyle and benefits can also be obtained in frail individuals who start exercising at an advanced age. Multicomponent programs combining mainly aerobic and resistance training should be included in the oldest old, particularly during disuse situations such as hospitalization. However, evidence is still needed to support the effectiveness of passive physical strategies including neuromuscular electrical stimulation or vibration for the prevention of disuse-induced negative adaptations in those oldest old people who are unable to do physical exercise. © 2019 American Physiological Society. Compr Physiol 9:1281-1304, 2019.

Physical Exercise and Mitochondrial Disease: Insights From a Mouse Model

Purpose: Mitochondrial diseases (MD) are among the most prevalent neuromuscular disorders. Unfortunately, no curative treatment is yet available. This study analyzed the effects of exercise training in an animal model of respiratory chain complex I deficiency, the Harlequin (Hq) mouse, which replicates the clinical features of this condition.

Methods: Male heterozygous Harlequin (Hq/Y) mice were assigned to an “exercise” (n = 10) or a “sedentary” control group (n = 11), with the former being submitted to an 8 week combined exercise training intervention (aerobic + resistance training performed five times/week). Aerobic fitness, grip strength, and balance were assessed at the beginning and at the end of the intervention period in all the Hq mice. Muscle biochemical analyses (with results expressed as percentage of reference data from age/sex-matched sedentary wild-type mice [n = 12]) were performed at the end of the aforementioned period for the assessment of major molecular signaling pathways involved in muscle anabolism (mTOR activation) and mitochondrial biogenesis (proliferator activated receptor gamma co-activator 1α [PGC-1α] levels), and enzyme activity and levels of respiratory chain complexes, and antioxidant enzyme levels.

Results: Exercise training resulted in significant improvements in aerobic fitness (−33 ± 13 m and 83 ± 43 m for the difference post- vs. pre-intervention in total distance covered in the treadmill tests in control and exercise group, respectively, p = 0.014) and muscle strength (2 ± 4 g vs. 17 ± 6 g for the difference post vs. pre-intervention, p = 0.037) compared to the control group. Higher levels of ribosomal protein S6 kinase beta-1 phosphorylated at threonine 389 (156 ± 30% vs. 249 ± 30%, p = 0.028) and PGC-1α (82 ± 7% vs. 126 ± 19% p = 0.032) were observed in the exercise-trained mice compared with the control group. A higher activity of respiratory chain complexes I (75 ± 4% vs. 95 ± 6%, p = 0.019), III (79 ± 5% vs. 97 ± 4%, p = 0.031), and V (77 ± 9% vs. 105 ± 9%, p = 0.024) was also found with exercise training. Exercised mice presented with lower catalase levels (204 ± 22% vs. 141 ± 23%, p = 0.036).

Conclusion: In a mouse model of MD, a training intervention combining aerobic and resistance exercise increased aerobic fitness and muscle strength, and mild improvements were found for activated signaling pathways involved in muscle mitochondrial biogenesis and anabolism, OXPHOS complex activity, and redox status in muscle tissue.

Full-Squat as a Determinant of Performance in CrossFit

This study analyzed the relationship between CrossFit performance and power and strength variables measured in the full-squat exercise. Twenty male trained subjects (33±7 years) performed an incremental load full-squat test for assessment of the 1-repetition maximum (1RM) and the mean (Pmean) and peak (Ppeak) power. Performance in 5 different Workouts of the Day (WODs) was measured on different days, and overall CrossFit performance was determined as the sum of the scores obtained in these WODs. Athletes were then assigned to a high (HP) or low (LP) performance group based on the median score for overall performance. Correlation analysis between squat variables and performance was performed and between-group differences were assessed. Moderate to strong (r=0.47-0.69, p<0.05) positive correlations were found between squat variables and performance in the different WODs. Overall CrossFit performance was strongly and positively associated with absolute (r=0.62, p=0.01) and relative 1RM (r=0.65, p=0.07), and relative Pmean (r=0.56, p=0.02) and Ppeak (r=0.53, p=0.03). Large differences (effect sizes ranging 1.1-1.7, all p<0.05) were observed between HP and LP for absolute and relative 1RM, relative Pmean, and absolute and relative Ppeak. In summary, strength and power indexes measured in a squat test are positively associated with CrossFit performance.

Myokine/Adipokine Response to "Aerobic" Exercise: Is It Just a Matter of Exercise Load?

Purpose

Exercise health benefits are partly mediated by exertional changes in several myokines/adipokines. This study aimed to compare the acute response of some of these biomarkers to aerobic exercise performed at the intensity corresponding to the maximum fat oxidation rate (FATmax) or the “anaerobic” threshold (AT).

Methods

Following a cross-over, counterbalanced design, 14 healthy untrained men (23 ± 1 years) performed a 45-min exercise bout at their FATmax or AT intensity (been previously determined through incremental exercise tests). The concentration of interleukin (IL)-15, follistatin, myostatin, fibroblast-growth factor (FGF)-21, irisin, resistin, and omentin was measured at baseline and 0, 1, 3, 24, 48, and 72 h post-exercise.

Results

AT exercise was performed at a higher intensity (85 ± 8 vs. 52 ± 14% of maximal oxygen uptake [VO_{2 max}], p < 0.001) and induced a higher energy expenditure (p < 0.001) than FATmax, whereas a greater fat oxidation was observed in the latter (p < 0.001). A higher peak response of FGF-21 (+90%, p < 0.01) and follistatin (+49%, p < 0.05) was found after AT-exercise, as well as a trend toward a higher peak level of omentin (+13%, p = 0.071) and a greater decrease in resistin (−16%, p = 0.073).

Conclusion

Increasing exercise load (from FATmax to AT) results in a higher response of FGF-21, follistatin and omentin to aerobic exercise, with the subsequent potential cardiometabolic benefits. No effects were, however, observed on the remainder of biomarkers. Future research should address if manipulating other exercise variables (e.g., type, frequency) can promote a higher myokine/adipokine response.

Physical exercise and Prader-Willi syndrome: A systematic review

OBJECTIVE

The aim of this systematic review was to summarize evidence on the acute responses of individuals with Prader-Willi syndrome (PWS) to physical exercise, and on the effectiveness of long-term exercise interventions to improve the clinical manifestations of this syndrome.

DESIGN/METHODS

Relevant articles were identified in the electronic databases PubMed, Medline, CINAHL and SPORTDiscus (from inception to December 2018). Twenty-two studies including a total of 356 patients with PWS met all inclusion criteria and were included in the review.

RESULTS

Patients with PWS present with a decreased physical performance and impaired cardiorespiratory (maximal oxygen consumption, heart rate recovery after exercise) and hormonal (growth hormone release) responses to exercise. Most long-term exercise interventions have proven to decrease body mass while improving physical performance. Some benefits have also been reported in biochemical (glucose homeostasis, lipid profile) and biomechanical (gait pattern) variables, although there is controversy regarding the effects on body composition. No exercise-related adverse events have been reported in patients with PWS.

CONCLUSION

Physical exercise seems to be safe and effective for improving several phenotypes in PWS, notably physical fitness. However, further research is needed to confirm these results and especially to corroborate whether exercise per se or combined with dietary intervention is an effective coadjuvant treatment for reducing body mass in these patients.

Supplements with purported effects on muscle mass and strength

PURPOSE

Several supplements are purported to promote muscle hypertrophy and strength gains in healthy subjects, or to prevent muscle wasting in atrophying situations (e.g., ageing or disuse periods). However, their effectiveness remains unclear.

METHODS

This review summarizes the available evidence on the beneficial impacts of several popular supplements on muscle mass or strength.

RESULTS

Among the supplements tested, nitrate and caffeine returned sufficient evidence supporting their acute beneficial effects on muscle strength, whereas the long-term consumption of creatine, protein and polyunsaturated fatty acids seems to consistently increase or preserve muscle mass and strength (evidence level A). On the other hand, mixed or unclear evidence was found for several popular supplements including branched-chain amino acids, adenosine triphosphate, citrulline, β-Hydroxy-β-methylbutyrate, minerals, most vitamins, phosphatidic acid or arginine (evidence level B), weak or scarce evidence was found for conjugated linoleic acid, glutamine, resveratrol, tribulus terrestris or ursolic acid (evidence level C), and no evidence was found for other supplements such as ornithine or α-ketoglutarate (evidence D). Of note, although most supplements appear to be safe when consumed at typical doses, some adverse events have been reported for some of them (e.g., caffeine, vitamins, α-ketoglutarate, tribulus terrestris, arginine) after large intakes, and there is insufficient evidence to determine the safety of many frequently used supplements (e.g., ornithine, conjugated linoleic acid, ursolic acid).

CONCLUSION

 In summary, despite their popularity, there is little evidence supporting the use of most supplements, and some of them have been even proven ineffective or potentially associated with adverse effects.

Myokine Response to High-Intensity Interval vs. Resistance Exercise: An Individual Approach

Purpose: This study aimed to compare the response to acute exercise of several myokines/hormones involved in metabolic function between two types of training sessions that are growing in popularity for their purported cardiometabolic benefits, high-intensity interval (HIIT) and resistance training (RT). Methods: Seventeen healthy, non-athletic men (23 ± 3 years) participated in this cross-over study. They randomly performed a HIIT [with short (HIIT1) or long (HIIT2) intervals] or a RT session. The concentration of fibroblast-growth factor (FGF) 21, follistatin, ghrelin, interleukin-15, irisin, myostatin, and peptide YY was measured at baseline and 0, 1, 3, 24, 48, and 72 h post-exercise. An individual approach was adopted to determine the rate of responsiveness to each specific cytokine and training mode. Results: A significant condition (session type) by time interaction (p = 0.004) effect was observed for FGF21, with RT eliciting a greater area under the curve (AUC) concentration than HIIT1 (p = 0.02). The AUC for follistatin was significantly greater after HIIT2 compared with RT (p = 0.02). Individual responsiveness to all session types ranged between 19 and 93% depending on the cytokine. However, most subjects (71-100%) responded positively for all cytokines (except for irisin, with only 53% of responders) after 1+ session type. Conclusion: Except for FGF21, our results show no overall differences in the myokine response to HIIT or RT. A considerable individual variability was observed, with some subjects responding to some but not other training session types. Notwithstanding, most responded to at least one training session. Thus, it is mostly the individual response of each subject rather than general recommendations on type of training session (i.e., RT vs. HIIT or HIIT subtypes) that must be taken into consideration for maximizing cardiometabolic benefits in the context of personalized exercise prescription.

Is the Functional Threshold Power a Valid Surrogate of the Lactate Threshold?

PURPOSE

To analyze the relationship between functional threshold power (FTP) and the lactate threshold (LT).

METHODS

A total of 20 male cyclists performed an incremental test in which LT was determined. At least 48 h later, they performed a 20-min time trial, and 95% of the mean power output was defined as FTP. Participants were divided into recreational (peak power output < 4.5 W·kg-1; n = 11) or trained cyclists (peak power output > 4.5 W·kg-1; n = 9) according to their fitness status.

RESULTS

The FTP (240 [35] W) was overall not significantly different (effect size = 0.20; limits of agreement = -2.4% [11.5%]) from the LT (246 [24] W), and both markers were strongly correlated (r = .95; P < .0001). Accounting for the participants' fitness status, no significant differences were found between FTP and LT (effect size = 0.22; limits of agreement =2.1% [7.8%]) in trained cyclists, but FTP was significantly lower than the LT (P = .0004, effect size = 0.81; limits of agreement =-6.5% [8.3%]) in recreational cyclists. A significant relationship was found between relative peak power output and the bias between FTP and the LT markers (r = .77; P < .0001).

CONCLUSIONS

FTP is a valid field test-based marker for the assessment of endurance fitness. However, caution should be taken when using FTP interchangeably with LT, as the bias between markers seems to depend on the athlete's fitness status. Whereas FTP provides a good estimate of LT in trained cyclists, in recreational cyclists, it may underestimate LT.

Relationship Between Dryland Strength and Swimming Performance: Pull-Up Mechanics as a Predictor of Swimming Speed

Pérez-Olea, JI, Valenzuela, PL, Aponte, C, and Izquierdo, M. Relationship between dryland strength and swimming performance: pull-up mechanics as a predictor of swimming speed. J Strength Cond Res 32(6): 1637-1642, 2018-This study aimed to examine the validity of the countermovement jump (CMJ) and the pull-up exercise as predictors of swimming performance. Twelve young male swimmers (Mean ± SD, 19 ± 3 years; 75 ± 10 kg; 180 ± 6 cm) with a homogenous level of performance (50-m freestyle time [50F]: 26.41 ± 1.44 seconds, coefficient of variance: 5.5%) participated in this study. Subjects performed a test of a single pull-up (PU) and a test of maximum number of pull-ups until muscular failure (PUF), and the mechanics of the ascending phase were recorded using a lineal force transducer. The height reached in a single CMJ test and the mean height during 30 consecutive CMJs were also determined. The swimmers' 50-m leg-only swimming time (50L) was also registered. The 50F time was strongly correlated with different variables of the PU (r = -0.76 to -0.80; p ≤ 0.05) and PUF test (r = -0.64 to -0.88; p ≤ 0.05), but not with the number of pull-ups performed. A significant relationship between 50F and 50L was observed (r = 0.78; p ≤ 0.05), with no relationship between the CMJ tests and swimming performance. Furthermore, multiple linear regression showed that 50L and the relative loss of velocity during the PUF test accounted for 84% (p < 0.001) of the 50F performance variance. This study shows the validity of the analysis of pull-up mechanics and 50L to predict short-distance swimming performance in trained swimmers, confirming the importance of upper-limb strength and leg kick on this sport.

Exercise training in childhood cancer: A systematic review and meta-analysis of randomized controlled trials

INTRODUCTION

Physical capacity and quality of life (QoL) are typically impaired in children/adolescents with cancer. Our primary objective was to examine the effects of exercise training performed after diagnosis of any type of pediatric cancer on physical capacity-related endpoints, survival, disease relapse and adverse effects.

METHODS

(a) Search and selection criteria: Systematic review in Pubmed and Web of Science (until August 2018) of randomized controlled trials (RCTs) of exercise interventions in children with cancer during treatment or within one year after its end. (b) Data collection: Two authors independently identified studies meeting inclusion criteria, extracted data, and assessed risk of bias using standardized forms. When needed, we contacted authors to request clarifications or additional data. (c) Statistical Analysis: The pooled standardized mean differences (SMD) were calculated for those endpoints for which a minimum of three RCTs used the same assessment method. We also calculated the pooled odds ratio (OR) of dying or having a tumor relapse.

RESULTS

Eight RCTs (n = 283 patients) were included in the systematic review. Of these, five studies (n = 173) could be meta-analyzed. Exercise training during pediatric cancer treatment significantly improves patients' functional mobility, as assessed with the timed up and down stairs test (SMD: -0.73, p < 0.001) and does not affect mortality (OR: 0.85, p = 0.76) or relapse risk (OR: 0.96, p = 0.94).

CONCLUSIONS

Exercise training in children with cancer improves functional mobility. More RCTs analyzing the effects of supervised exercise interventions are needed, as well as the development of a core-set of outcomes in pediatric oncology exercise research.

Intradialytic Exercise: One Size Doesn't Fit All

Purpose: Hemodialysis patients commonly have impaired physical performance and mental health. We studied the effects of an intradialytic exercise program on these variables.

Methods: 27 patients (33% women; 68 ± 13 years) were enrolled in a 14-week intradialytic endurance-resistance training program (‘exercise’ group, 40 programmed sessions per patient); 40 hemodialysis patients (28% women; 68 ± 11 years) performing no exercise during the same time length were used as controls. Endpoints included physical performance (6-min walk test [6MWT], 10-repetition sit to stand [STS-10] and handgrip strength), emotional status (Beck’s depression inventory and State-Trait Anxiety Inventory), and mental and physical component scores of the short-from (SF)-12 Health Survey.

Results: There were no differences (p> 0.05) between groups at baseline for sex distribution, or mean age, body mass index and time spent on dialysis. Exercise benefits were observed for 6MWT (11 and −3% for the exercise and control groups, respectively; p < 0.001), STS-10 performance time (-22 and 6%; p < 0.001) and handgrip strength (4 and −4%; p < 0.02). No significant benefits (p> 0.05) were observed for emotional status endpoints or SF-12 component scores. Despite significant benefits on physical performance, the proportion of clinically meaningful responders was low (<50%). Responsiveness was dependent on baseline physical performance (p < 0.05) but not on age or sex (p > 0.05).

Conclusion: A 14-week intradialytic training program induced significant improvements on physical performance. However, the rate of clinically meaningful responders observed in the present study was low, being the level of responsiveness dependent on baseline physical status. Efforts to individualize exercise prescription are needed in clinical practice.

Relationship between skeletal muscle contractile properties and power production capacity in female Olympic rugby players

This study aimed to determine which contractile properties measured by tensiomyography (TMG) could better differentiate athletes with high- and low-power values, as well as to analyse the relationship between contractile properties and power production capacity. The contractile properties of the vastus medialis (VM), rectus femoris (RF) and vastus lateralis (VL) of an Olympic women's Rugby Sevens team (n = 14) were analysed before a Wingate test in which their peak power output (PPO) was determined. Athletes were then divided into a high-power (HP) and a low-power (LP) group. HP presented an almost certainly higher PPO (9.8 ± 0.3 vs. 8.9 ± 0.4 W kg^-1, ES = 3.00) than LP, as well as a very likely lower radial displacement (3.39 ± 1.16 vs. 5.65 ± 1.50 mm, ES = 1.68) and velocity of deformation (0.08 ± 0.02 vs. 0.13 ± 0.03 mm ms^-1, ES = 1.87) of the VL. A likely lower time of delay was observed in HP for all analysed muscles (ES > 0.60). PPO was very largely related to the radial displacement (r = -0.75, 90% CI = -0.90 to -0.44) and velocity of deformation (r = -0.70, 90% CI = -0.87 to -0.34) of the VL. A large correlation was found between PPO and the time of delay of the VL (r = -0.61, 90% CI = -0.84 to -0.22). No correlations were found for the contractile properties of RF or VM. These results highlight the importance of VL contractile properties (but not so much those of RF and VM) for maximal power production and suggest TMG as a practical technique for its evaluation.

Performance and physiological analysis of 500 km non-stop cycling: a case study

Ultra-endurance sports have gained popularity over the last years. In this case, a well-trained cyclist completed 503.5 km non-stop (33.3 km.h^-1). Speed and power output were reduced during the trial, being the reduction of power attributable to changes in pedal velocity rather than pedal forces. Heart rate (HR) showed an initial cardiovascular drift and progressively decreased independently of power. A decreased HR variability, a marked inflammatory response, signs of muscle damage and alterations of the haematological profile were observed after the trial. These adverse physiological effects were still present 24-48 h after exercise. A reduction in handgrip maximal voluntary contraction was observed immediately after the trial and 24 h later despite these muscles being minimally active during exercise. These findings show the high levels of stress to which the organism is subjected during ultra-endurance exercise even in the case of a trained cyclist.