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Dixon, PG, Kraemer, W J, Volek, JS, Howard, RL, Gomez, AL, Comstock, BA, Dunn-Lewis, C, Fragala, MS, Hooper, DR, Hakkinen, K, and Maresh, CM. The impact of cold-water immersion on power production in the vertical jump and the benefits of a dynamic exercise warm-up. E Strength Cond Res 24(12): 3313-3317, 2010-The purpose of this study was to examine the influence of a cold treatment and a dynamic warm-up on lower body power in the form of a countermovement vertical jump (CMVJ). Nine physically active men, who were either current or ex-National Collegiate Athletic Association (NCAA) Division 1 athletes, consented to participate in the study. Using a balanced, randomized presentation and a within-subject design, each subject performed 4 environmental and warm-up protocols (i.e., ambient temperature without warm-up, ambient temperature with warm-up, cold without warm-up, or cold with warm-up). Two sets of 3 maximal effort CMVJs were performed on a force plate at each testing time point. For each protocol, the subjects completed a pretest set of CMVJ (pretreatment [PRE]), were then exposed to 1 of the 2 temperature treatments, completed another set of CMVJ (initial [IT]), then either went through a 15-minute warm-up, or were asked to sit in place. Then a final set of CMVJs was completed (posttreatment [PT]). The primary finding in this study was that warm-up was effective in offsetting the negative effects of cold exposure on CMVJ power. There was a significant main effect for Time (PRE > PT > IT), and there was a significant (p [less than or equal to] 0.05) main effect for Trial (AMB = AMBWU > COLDWU > COLD). Because athletic competitions happen in various colder climates, it is important to make sure that a proper warm-up be completed to maximize the athlete's power output. The results of this study demonstrate that when athletes are exposed to cold conditions, it is recommended that before practice or play, a dynamic warm-up be employed to optimize performance. KEY WORDS environmental, anaerobic, sport, neuromuscular

The primary purpose of this investigation was to evaluate the influence of a whole body compression garment on recovery from a typical heavy resistance training workout in resistance-trained men and women. Eleven men (mean [+ or -] SD: age, 23.0 [+ or -] 2.9 years) and 9 women (mean [+ or -] SD: age 23.1 [+ or -] 2.2 years) who were highly resistance trained gave informed consent to participate in the study. A within-group (each subject acted as their own control), balanced, and randomized treatment design was used. Nutritional intakes, activity, and behavioral patterns (e.g., no pain medications, ice, or long showers over the 24 hours) were replicated 2 days before each test separated by 72 hours. An 8-exercise whole body heavy resistance exercise protocol using barbells (3 sets of 8-10 repetition maximum, 2.0-to 2.5-minute rest) was performed after which the subject showered and put on a specific whole body compression garment one designed for women and one for men (CG) or just wore his/her normal noncompression clothing (CON). Subjects were then tested after 24 hours. Dependent measures included sleep quality, vitality rating, resting fatigue rating, muscle soreness, muscle swelling via ultrasound, reaction movement times, bench throw power, countermovement vertical jump power, and serum concentrations of creatine kinase (CK) measured from a blood sample obtained via venipuncture of an arm vein. We observed significant (p [less than or equal to] 0.05) differences between CG and CON conditions in both men and women for vitality (CG > CON), resting fatigue ratings (CG < CON), muscle soreness (CG < CON), ultrasound measure swelling (CG < CON), bench press throw (CG > CON), and CK (CG < CON). A whole body compression garment worn during the 24-hour recovery period after an intense heavy resistance training workout enhances various psychological, physiological, and a few performance markers of recovery compared with non-compressive control garment conditions. The use of compression appears to help in the recovery process after an intense heavy resistance training workout in men and women. KEY WORDS power, restoration, muscle damage, repair, soreness, mood states

The purpose of this study was to examine the relationship between lower-body muscle structure and vertical jump performance. Twenty-five resistance-trained men (age, 23.3 [+ or -] 3.2 years; height, 176.1 [+ or -] 7.4 cm; and weight, 86.2 [+ or -] 11.6 kg) took part in both anatomical and jump performance testing. Muscle fascicle thickness, fascicle length, and pennation angle were analyzed for the vastus lateralis (VL) and the lateral gastrocnemius (LG). Jump height and both relative and absolute power were measured for the squat jump (SJ), countermovement jump (CMJ), and depth drop jump (DDJ). Regressions were used to determine if jump performance could be predicted using the aforementioned structures. No VL measurements were significantly correlated with any of the jump measures. Lateral gastrocnemius pennation angle was a significant but weak predictor of jump height for all 3 jump types (SJ: [r.sup.2] = 0.212, p = 0.021; CMJ: [r.sup.2] = 0.186, p = 0.018; DDJ: [r.sup.2] = 0.263, p = 0.005). When comparing jump height at increasing preloads, none of the variables of interest could significantly predict the jump height differences between CMJ and SJ. However, LG fascicle length had a weak but significant inverse relationship with DDJ-CMJ ([r.sup.2] = 0.152; p = 0.031). Lateral gastrocnemius thickness was the strongest predictor of absolute power for all jump types and between jump types (SJ: [r.sup.2] = 0.181, p = 0.034; CMJ: [r.sup.2] = 0.201, p = 0.014; DDJ: [r.sup.2] = 0.122, p = 0.049; CM-SJ: [r.sup.2] = 0.201, p = 0.014; DDJ-CMJ: [r.sup.2] = 0.146, p = 0.034). Lateral gastrocnemius pennation angle was also the best predictor of relative power for all 3 jump types and between jump types (SJ: [r.sup.2] = 0.172, p = 0.038; CMJ: [r.sup.2] = 0.416, p = 0.000; DDJ: [r.sup.2] = 0.167, p = 0.024; CMJ-SJ: [r.sup.2] = 0.391, p = 0.000; DDJ-CMJ: [r.sup.2] = 0.136, p = 0.039). Results for jump performance differ from those previously found for sprinting in that greater pennation and shorter fascicles, positively predicting jumping ability at increased prestretch loads reinforcing the need for training specificity. Our findings in resistance-trained men indicate that where jumping is vital to athletic success one can benefit from developing LG muscle architecture along with addressing eccentric strength. KEY WORDS ultrasound, ultrasonogrpahy, pennation, fascicle, preaugmented loading