Efectos del entrenamiento en slackline sobre la resistencia del core y el equilibrio dinámico

Slackline challenges balance by walking on a tensioned strap, where the trunk muscles help to maintain or regain balance. This study aimed to compare a cohort of individuals who regularly practiced slackline and physically inactive individuals on core endurance (CE) and dynamic balance (DB) and to determine whether CE is associated with years of slackline practice. Nine individuals (7 men) who practiced slackline regularly (SG; age= 24.5±3.6 years) and nine physically inactive individuals (7 men) (CG; age= 23.2±3.3 years) were compared. CE was assessed with the McGill battery (trunk flexor, extensor, and side-bridge test) and the plank test. DB was measured with the modified star excursion balance test in stable and unstable conditions. The SG maintained a 36.2% and 45% longer time in left lateral bridge (p=.049) and plank (p=.031), respectively, compared to the CG. The distance achieved in the stable DB test was similar between groups, but in unstable condition was 37.8% greater (p=.016) in SG in both legs and 46.6% greater in the non-dominant leg (p=.039) compared to CG. The SG showed a correlation between years of slackline practice and flexor (r=.674; p=.046), right lateral (r=.765; p=.016) and left (r=.730; p=.026) trunk endurance. In conclusion, those who practice slackline maintain a longer time in the plank and left lateral bridge test and achieve a higher reach distance in unstable DB compared to physically inactive individuals who do not practice slackline.El slackline desafía el equilibrio al caminar sobre una cinta en tensión, donde los músculos del tronco ayudan a mantener o recuperar el equilibrio. El objetivo de este estudio fue comparar individuos que practicaban slackline e individuos inactivos fisicamente (IF) en resistencia del core (RC) y equilibrio dinámico (ED), y conocer si la RC se asocia a los años de practica de slackline. Nueve individuos (7 hombres) que practicaban slackline regularmente (GS; edad= 24.5±3.6 años) y nueve individuos IF (7 hombres) (GC; edad= 23.2±3.3 años) fueron comparados. La RC se evaluó con la bateria de McGill (prueba de flexores y extensores de tronco y puente lateral) y la prueba de la plancha. El ED se midió con la prueba de excursión de la estrella modificada en condiciones estables e inestables. El GS mantuvo un tiempo 36.2% y 45% mayor en puente lateral izquierdo (p=.049) y plancha (p=.031) respectivamente comparado con el GC. La distancia alcanzada en la prueba de ED estable fue similar entre grupos, pero en condición inestable fue 37.8% mayor (p=.016) en GS en ambas piernas y 46.6% mayor en la pierna no dominante (p=.039) comparado al GC. El GS mostró una correlación entre años de práctica de slackline y resistencia flexora (r=.674; p=.046), lateral derecha (r=.765; p=.016) e izquierda (r=.730; p=.026) de tronco. En conclusión, quienes practican slackline mantienen un tiempo mayor la prueba de la plancha y puente lateral izquierdo y logran un mayor alcance en ED inestable comparados con individuos IF que no lo practican

Elites Do Not Deplete – No Effect of Prior Mental Exertion on Subsequent Shooting Performance in Elite Shooters

In order to perform at the highest level, elite shooters have to remain focused during the whole course of a tournament, which regularly lasts multiple hours. Investing self-control over extended time periods is often associated with lower levels of perceived self-control strength (i.e., the subjective estimation of how much mental effort one is capable of investing in a given task) and impaired performance in several sports-related domains. However, previous findings on the effects of prior self-control efforts on shooting performance have been mixed, as elite shooters seem to be less affected by preceding self-control demanding tasks than sub-elite athletes. Therefore, the aim of the present study was to investigate the effects of self-control on shooting performance in elite shooters. Hence, we randomly assigned elite shooters to an experimental (n = 12) or a control condition (n = 11) and asked them to perform a series of 40 shots at baseline (T1) and again after a task which either did or did not require self-control (T2). Additionally, we continuously measured the shooters’ level of perceived self-control strength. We assumed that in elite athletes, shooting accuracy as well as the perceived level of self-control strength would not be significantly affected over time from T1 to T2 in both conditions. In line with our assumptions, Bayesian linear mixed effect models revealed that shooting performance remained relatively stable in both conditions over time and the conditions also did not differ significantly in their perceived levels of self-control strength. Contrary to resource-based theories of self-control, these results speak against the idea of a limited self-control resource as previous acts of self-control did not impair subsequent shooting performance in elite athletes.publishe

Brain structure can mediate or moderate the relationship of behavior to brain function and transcriptome. A preliminary study

Abnormalities in motor-control behavior, which have been with concussion and head acceleration events (HAE), can be quantified using virtual reality (VR) technologies. Motor-control behavior has been consistently mapped to the brain's somatomotor network (SM) using both structural (sMRI) and functional MRI (fMRI). However, no studies habe integrated HAE, motor-control behavior, sMRI and fMRI measures. Here, brain networks important for motor-control were hypothesized to show changes in tractography-based diffusion weighted imaging [difference in fractional anisotropy (dFA)] and resting-state fMRI (rs-fMRI) measures in collegiate American football players across the season, and that these measures would relate to VR-based motor-control. We firther tested if nine inflammation-related miRNAs were associated with behavior-structure-function variables. Using permutation-based mediation and moderation methods, we found that across-season dFA from the SM structural connectome (SM-dFA) mediated the relationship between across-season VR-based Sensory-motor Reactivity (dSR) and rs-fMRI SM fingerprint similarity (p = 0.007 and Teff = 47%). The interaction between dSR and SM-dFA also predicted (pF = 0.036, pbeta3 = 0.058) across-season levels of dmiRNA-30d through permutation-based moderation analysis. These results suggest (1) that motor-control is in a feedback relationship with brain structure and function, (2) behavior-structure-function can be connected to HAE, and (3) behavior-structure might predict molecular biology measures.Comment: 62 pages, 4 figures, 2 table

Slacklining as therapy to address non-specific low back pain in the presence of multifidus arthrogenic muscle inhibition

Low back pain (LBP) represents the most prevalent, problematic and painful of musculoskeletal conditions that affects both the individual and society with health and economic concerns. LBP is a heterogeneous condition with multiple diagnoses and causes. In the absence of consensus definitions, partly because of terminology inconsistency, it is further referred to as non-specific LBP (NSLBP). In NSLBP patients, the lumbar multifidus (MF), a key stabilizing muscle, has a depleted role due to recognized myocellular lipid infiltration and wasting, with the potential primary cause hypothesized as arthrogenic muscle inhibition (AMI). This link between AMI and NSLBP continues to gain increasing recognition. To date there is no 'gold standard' or consensus treatment to alleviate symptoms and disability due to NSLBP, though the advocated interventions are numerous, with marked variations in costs and levels of supportive evidence. However, there is consensus that NSLBP management be cost-effective, self-administered, educational, exercise-based, and use multi-modal and multi-disciplinary approaches. An adjuvant therapy fulfilling these consensus criteria is 'slacklining', within an overall rehabilitation program. Slacklining, the neuromechanical action of balance retention on a tightened band, induces strategic indirect-involuntary therapeutic muscle activation exercise incorporating spinal motor control. Though several models have been proposed, understanding slacklining's neuro-motor mechanism of action remains incomplete. Slacklining has demonstrated clinical effects to overcome AMI in peripheral joints, particularly the knee, and is reported in clinical case-studies as showing promising results in reducing NSLBP related to MF deficiency induced through AMI (MF-AMI). Therefore, this paper aims to: rationalize why and how adjuvant, slacklining therapeutic exercise may positively affect patients with NSLBP, due to MF-AMI induced depletion of spinal stabilization; considers current understandings and interventions for NSLBP, including the contributing role of MF-AMI; and details the reasons why slacklining could be considered as a potential adjuvant intervention for NSLBP through its indirect-involuntary action. This action is hypothesized to occur through an over-ride or inhibition of central down-regulatory induced muscle insufficiency, present due to AMI. This subsequently allows neuroplasticity, normal neuro-motor sequencing and muscle re-activation, which facilitates innate advantageous spinal stabilization. This in-turn addresses and reduces NSLBP, its concurrent symptoms and functional disability. This process is hypothesized to occur through four neuro-physiological processing pathways: finite neural delay; movement-control phenotypes; inhibition of action and the innate primordial imperative; and accentuated corticospinal drive. Further research is recommended to investigate these hypotheses and the effect of slacklining as an adjuvant therapy in cohort and control studies of NSLBP populations