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http://www.ncbi.nlm.nih.gov/pubmed/25766044
Jeopardizing Christmas: Why spoiled kids and a tight schedule could make Santa Claus fall?
AbstractQuoteSanta Claus’ spatio-temporal gait characteristics, ground reaction forces during treadmill walking as well as postural sway during loaded, unloaded and cognitive interference tasks were examined in order to estimate his fall risk.
Seventeen healthy males, disguised as researchers and students (age: 30 ± 10 years; height: 179 ± 6 years; weight: 76 ± 7 kg; BMI: 24 ± 2 kg/m2; physical activity: 12 ± 4 h/week) and who still believe in Santa Claus randomly underwent balance and gait analyses with and without cognitive interference. The conditions were to be dressed as “Santa Claus” (wearing costume consisting of a beard, cap, robe, heavy sack with a load of 20 kg) or dressed in “normal clothing” (no costume). Spatiotemporal gait parameters (walking velocity, gait variability and stride time, length and width), ground reaction forces (GRF) (left- and right-sided heel strike and push off) and postural sway (30 s tandem stance on a force plate) were measured.
“Santa-effects” (0.001 < p < 0.05; ) and “Dual-task effects” (0.001 < p < 0.003; ) were found for postural sway (increased sway), GRF (decreased forces for dual tasking, increased forces for the Santa condition) and the majority of spatio-temporal gait parameters. Significant “Santa” × “Dual-Task” interaction effects were not observed (0.001 < p < 0.05; ). Relevant leg effects of GRF during walking were not found.
Santa Claus faces a tremendously increased risk of falling when carrying his Christmas sack with 20 kg of presents. Cognitive loads also impair his neuromuscular performance. It is recommended that Santa trains his strength and balance before Christmas and also to avoid filling his sack with more than 20 kg of presents. Also, cognitive training may help to improve his dual task performance.
Andrew, really appreciate the time you put into that post. That link was also a good read. One question I have after digesting all of that is:
Does the concentrated loading block HAVE to be accumulated fatigue from high volume/high intensity weight room training? Can't the accumulated fatigue in this block be from a mixture of high intensity weight room stuff AND high intensity plyo's (volume split between the two)? Because bottom line, the fatigue accumulated that creates supercompensation is CNS fatigue and both weights AND high intensity plyo's can induce this CNS fatigue (thus reducing maximal and especially explosive strength) right?
Lochev got caught using some GNRH analogue - record stripped
Abstract
Background Decreased postural stability is a primary risk factor for lower limb musculoskeletal injuries. During athletic competitions, cryotherapy may be applied during short breaks in play or during half-time; however its effects on postural stability remain unclear.
Objective To investigate the acute effects of a 15-minute ankle joint cryotherapy application on dynamic postural stability.
Design Experimental study.
Setting University biomechanics laboratory.
Participants 29 elite level collegiate male field-sport athletes.
Interventions Participants were tested on the anterior (ANT), posterior-lateral (PL) and posterior-medial (PM) reach directions of the Star Excursion Balance Test (SEBT) both pre- and post- a 15-minute ankle joint cryotherapy application.
Main outcome measurements Normalized reach distances, along with sagittal plane kinematics of the hip, knee and ankle joints, as well as associated MVELO and AREAsw of the center-of-pressure (COP) path during the performance of the ANT, PL and PM reach directions of the SEBT.
Results There was a statistically significant decrease in ANT, PL and PM reach direction reach distance scores from pre-cryotherapy to post-cryotherapy (P≤.05). No significant differences were observed in hip, knee or ankle joint sagittal plane kinematics (P≥.05). There was a significant decrease in MVELO of the COP path from pre-cryotherapy to post-cryotherapy (P≤.05) in all reach directions (P≤.05). AREAsw of the COP path was significantly decreased from pre-cryotherapy to post-cryotherapy in the ANT and PM reach directions (P≥.05).
Conclusions The results of the present study indicate that dynamic postural stability is adversely affected immediately following cryotherapy application to the ankle joint.
Abstract
The purpose of this study was to determine the effect of cryotherapy on the inflammatory response to muscle-damaging exercise using a randomized trial. Twenty recreationally active males completed a 40-min run at a −10 % grade to induce muscle damage. Ten of the subjects were immersed in a 5 °C ice bath for 20 min and the other ten served as controls. Knee extensor peak torque, soreness rating, and thigh circumference were obtained pre- and post-run, and 1, 6, 24, 48, and 72 h post-run. Blood samples were obtained pre- and post-run, and 1, 6 and 24 h post-run for assay of plasma chemokine ligand 2 (CCL2). Peak torque decreased from 270 ± 57 Nm at baseline to 253 ± 65 Nm post-run and increased to 295 ± 68 Nm by 72 h post-run with no differences between groups (p = 0.491). Soreness rating increased from 3.6 ± 6.0 mm out of 100 mm at baseline to 47.4 ± 28.2 mm post-run and remained elevated at all time points with no differences between groups (p = 0.696). CCL2 concentrations increased from 116 ± 31 pg mL−1 at baseline to 293 ± 109 pg mL−1 at 6 h post-run (control) and from 100 ± 27 pg mL−1 at baseline to 208 ± 71 pg mL−1 at 6 h post-run (cryotherapy). The difference between groups was not significant (p = 0.116), but there was a trend for lower CCL2 in the cryotherapy group at 6 h (p = 0.102), though this measure was highly variable. In conclusion, 20 min of cryotherapy was ineffective in attenuating the strength decrement and soreness seen after muscle-damaging exercise, but may have mitigated the rise in plasma CCL2 concentration. These results do not support the use of cryotherapy during recovery.
We investigated the effects of topical icing after muscle contusion injury on angiogenesis in regenerating skeletal muscle. Male Wistar rats were subjected to contusion injury by dropping a cylindrical-shaped weight (370 g) on the biceps femoris muscle of one leg. Within 5 min after injury, a block of ice (contained within a paper cup) was applied to the skin surrounding the muscle for 20 min. Control groups received no ice treatment. The rats were euthanized at 1, 3, 7 and 28 days post-injury (n=24 per time point). In 12 rats in each group, a punch biopsy (diameter: 8 mm) was taken from the region of injury and fixed in 10% neutral buffered formalin. Tissue sections (5 μm) were then mounted on glass slides for immunohistochemical analysis of CD68+ macrophages, vascular endothelial growth factor (VEGF) and von Willebrand's factor (vWF). After euthanasia, the others rats in each group were flushed with heparinized saline, and then perfused with a radio-opaque contrast agent using an infusion pump. Muscle biopsies were also collected from these rats, and analyzed to determine blood vessel volume and number using high resolution micro computed tomography. Macrophage numbers were lower at all time points, VEGF expression and vessel number were lower at 3 days and vWF expression and vessel volume were lower at 3 and 7 days post-injury in the icing group versus the non-icing group (p<0.05). By contrast, VEGF expression and vessel number were higher at 28 days post-injury in the icing group versus the non-icing group (p<0.05). In conclusion, topical icing suppressed inflammation but also delayed angiogenesis in regenerating muscle. These findings challenge the practice of using ice to treat muscle injuries.
Abstract: Tseng, C-Y, Lee, J-P, Tsai, Y-S, Lee, S-D, Kao, C-L, Liu, T-C, Lai, C-S, Harris, MB, and Kuo, C-H. Topical Cooling (Icing) Delays Recovery From Eccentric Exercise–Induced Muscle Damage. J Strength Cond Res 27(5): 1354–1361, 2013—It is generally thought that topical cooling can interfere with blood perfusion and may have positive effects on recovery from a traumatic challenge. This study examined the influence of topical cooling on muscle damage markers and hemodynamic changes during recovery from eccentric exercise. Eleven male subjects (age 20.2 ± 0.3 years) performed 6 sets of elbow extension at 85% maximum voluntary load and randomly assigned to topical cooling or sham groups during recovery in a randomized crossover fashion. Cold packs were applied to exercised muscle for 15 minutes at 0, 3, 24, 48, and 72 hours after exercise. The exercise significantly elevated circulating creatine kinase-MB isoform (CK-MB) and myoglobin levels. Unexpectedly, greater elevations in circulating CK-MB and myoglobin above the control level were noted in the cooling trial during 48–72 hours of the post-exercise recovery period. Subjective fatigue feeling was greater at 72 hours after topical cooling compared with controls. Removal of the cold pack also led to a protracted rebound in muscle hemoglobin concentration compared with controls. Measures of interleukin (IL)-8, IL-10, IL-1β, and muscle strength during recovery were not influenced by cooling. A peak shift in IL-12p70 was noted during recovery with topical cooling. These data suggest that topical cooling, a commonly used clinical intervention, seems to not improve but rather delay recovery from eccentric exercise–induced muscle damage.
