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Wagle, JP, Cunanan, AJ, Carroll, KM, Sams, ML, Wetmore, A, Bingham, GE, Taber, CB, DeWeese, BH, Sato, K, Stuart, CA, and Stone, MH. Accentuated eccentric loading and cluster set configurations in the back squat: a kinetic and kinematic analysis. J Strength Cond Res 35(2): 420-427, 2021-This study examined the kinetic and kinematic differences between accentuated eccentric loading (AEL) and cluster sets in trained male subjects (age = 26.1 ± 4.1 years, height = 183.5 ± 4.3 cm, body mass = 92.5 ± 10.5 kg, and back squat to body mass ratio = 1.8 ± 0.3). Four load condition sessions consisted of traditionally loaded (TL) "straight sets," TL cluster (TLC) sets, AEL cluster (AEC) sets, and AEL "straight sets" where only the first repetition had eccentric overload (AEL1). An interrepetition rest interval of 30 seconds was prescribed for both TLC and AEC. Concentric intensity for all load conditions was 80% 1 repetition maximum (1RM). Accentuated eccentric loading was applied to repetitions using weight releasers with total eccentric load equivalent to 105% of concentric 1RM. Traditionally loaded cluster had statistically greater concentric outputs than TL. Furthermore, statistically greater eccentric and concentric outputs were observed during AEC compared with TL with the exception of peak power. Statistically greater concentric characteristics were observed in TLC compared with AEL1, but statistically greater eccentric outputs were observed in AEL1. In the 2 cluster set conditions, statistically greater concentric rate of force development (RFDCON) (d = 0.470, p0.001) and average velocity (vavg) (d = 0.560, p0.001) in TLC compared with AEC were observed. However, statistically greater eccentric work (WECC) (d = 2.096, p0.001) and eccentric RFD (RFDECC) (d = 0.424, p0.001) were observed in AEC compared with TLC. Overall, eccentric overload demonstrated efficacy as a means of increasing eccentric work and RFD, but not as a means of potentiating concentric output. Finally, interrepetition rest seems to have the largest influence on concentric power output and RFD.

Travis, SK, Mizuguchi, S, Stone, MH, Sands, WA, and Bazyler, CD. Preparing for a national weightlifting championship: A case series. J Strength Cond Res 34(7): 1842-1850, 2020-This study aimed to characterize psychological, physiological, and performance changes of a high-level female (24.5 years; 53.8 ± 0.3 kg; 155.4 cm) and male (25.8 years; 92.7 ± 1.2 kg; 189 cm) weightlifter over 28 weeks while preparing for a national championship. Body mass, hydration, psychological inventories, serum biomarkers, vastus lateralis muscle cross-sectional area (CSA), and squat jump (SJ) performance were assessed weekly beginning 11 weeks from the competition date. Weightlifting performance goals were met for the female athlete (actual total = 159 kg) but not for the male athlete (actual total = 292 kg). Reductions in vastus lateralis CSA possibly took place the week leading into competition for both athletes. Both athletes reported positive recovery-stress states on the day of competition relative to baseline values. Fluctuations between steroid hormone concentrations and inflammatory markers were unpredictable and inconsistent for both athletes throughout the training program. Unloaded SJ height and rate of force development were the highest on competition day for both athletes. Based on these findings, it is possible for high-level male and female weightlifters to achieve and maintain peak preparedness 3-4 days before competition following a 1-week overreach and 3-week exponential taper, where training volume-load is reduced by half and intensity maintained or slightly increased relative to pretaper values. Furthermore, the short recovery and stress scale and SJ testing seem to be useful tools for sport scientists and coaches when monitoring high-level weightlifters preparing for competition.

Ishida, A, Suarez, DG, Travis, SK, Slaton, JA, White, JB, Bazyler, CD, and Stone, MH. Intrasession and intersession reliability of isometric squat, midthigh pull, and squat jump in resistance-trained individuals. J Strength Cond Res 37(1): 18-26, 2023-The purposes of this study were to investigate intrasession and intersession reliability of variables obtained from squat jump (SJ), shortened isometric midthigh pull (IMTP), and isometric squat (ISQ) protocols and to evaluate relationships between isometric and dynamic performance and 1 repetition maximum (1RM) back squat (BSQ). Eleven moderately resistance-trained men participated (27.8 ± 3.9 years; 175.0 ± 7.2 cm; 87.2 ± 11.4 kg). Subjects completed familiarization in the IMTP and ISQ, followed by 1RM BSQ at least 48 hours before the first performance test. Two performance tests occurred at 7-day intervals including SJ, IMTP, and ISQ. SJ variables included jump height (SJH), body mass (BM), peak force (PF), and peak power (PP). Isometric midthigh pull and ISQ variables included isometric peak force (IPF); relative IPF; rate of force development at 90, 200, and 250 milliseconds; and impulse at 90, 200, and 250 milliseconds. SJ, IMTP, and ISQ kinetic variables were considered reliable if intraclass correlations (ICCs) and coefficients of variations (CVs) were0.80 and10%. Intrasession and intersession reliability criteria were met for SJH, BM, PF, and PP (ICC = 0.91-1.00, CV = 0.5-9.1%). Isometric peak force and impulse at 200 and 250 milliseconds met intrasession and intersession reliability criteria for IMTP and ISQ (ICC = 0.90-0.99, CV = 2.1-8.1%). Significant large correlation was observed between 1RM BSQ and ISQ peak force (p = 0.038, r = 0.63), but not between 1RM BSQ and shortened IMTP peak force (p = 0.11, r = 0.50). Shortened IMTP and ISQ peak force and impulse are reliable kinetic variables, and ISQ peak force is indicative of 1RM BSQ in moderately resistance-trained men.

Travis, SK, Pritchard, HJ, Mujika, I, Gentles, JA, Stone, MH, and Bazyler, CD. Characterizing the tapering practices of United States and Canadian raw powerlifters. J Strength Cond Res 35(12S): S26-S35, 2021-The purpose of this study was to characterize the tapering practices used by North American powerlifters. A total of 364 powerlifters completed a 41-item survey encompassing demographics, general training, general tapering, and specific tapering practices. Nonparametric statistics were used to assess sex (male and female), competition level (regional/provincial, national, and international), and competition lift (squat, bench press, and deadlift). The highest training volume most frequently took place 5-8 weeks before competition, whereas the highest training intensity was completed 2 weeks before competition. A step taper was primarily used over 7-10 days while decreasing the training volume by 41-50% with varied intensity. The final heavy (>85% 1 repetition maximum [1RM]) back squat and deadlift sessions were completed 7-10 days before competition, whereas the final heavy bench press session was completed

Bazyler, CD, Mizuguchi, S, Zourdos, MC, Sato, K, Kavanaugh, AA, DeWeese, BH, Breuel, KF, and Stone, MH. Characteristics of a national level female weightlifter peaking for competition: A case study. J Strength Cond Res 32(11): 3029-3038, 2018-This study investigated physiological and performance changes of a national-level 69 kg female weightlifter after 3 competition phases over a 28-week training period. The athlete first trained for a regional championship (weeks 1-12), followed by a local competition (weeks 13-23) and the national championship (weeks 24-28). Body mass, vastus lateralis cross-sectional area (CSA), and unloaded and loaded squat jump performance were assessed weekly during each 4-week competition phase. Serum biomarkers and dynamic midthigh pulls were assessed before and after each competition phase. Weightlifting performance goals were met for the regional championship (total = 200 kg) and the local competition (total = 193 kg), but not the national championship (total = 196 kg). She lost more body mass in preparation for Nationals (-6.0 kg) compared with regionals (-2.5 kg) and the local competition (+2.2 kg). Vastus lateralis CSA very likely decreased after Nationals (precision = 99%, effect size = 2.08). Her testosterone:cortisol ratio likely increased (88%, 2.64), whereas interleukin-6 (79%, 2.47) and tumor necrosis factor-alpha (81%, 3.59) likely decreased after Nationals. Serum myostatin (99%, 1.95) and decorin (99%, 1.96) very likely decreased after the local competition. Unloaded squat jump height likely increased the week of regionals (89%, 0.95) and the local competition (99%, 1.83), whereas unloaded and loaded squat jump height possibly (69%, 0.99) and likely (82%, 1.52) decreased the week of Nationals. Dynamic midthigh pull vertical displacement likely increased after regionals (93%, 0.84) and likely decreased after Nationals (94%, 0.87). These findings indicate that biomarkers of stress, inflammation, and hypertrophy are related to changes in training volume-load; however, performance measures are needed to assess competition preparedness. Considering the reductions in muscle CSA corresponding with the large reductions in body mass and underperformance at the national championship, sport scientists, and coaches should instruct weightlifters to not attempt large losses in body mass (e.g., >3 kg) close to competition (e.g.

Sams, ML, Sato, K, DeWeese, BH, Sayers, AL, and Stone, MH. Quantifying changes in squat jump height across a season of men's collegiate soccer. J Strength Cond Res 32(8): 2324-2330, 2018-The purposes of this study were to examine the effectiveness of an athlete monitoring program in managing athlete neuromuscular fatigue across a men's collegiate soccer season as measured by changes in squat jump (SJ) height and to compare possible changes with the session rating of perceived exertion (sRPE) training load (TL). Eighteen outfield Division I men's college soccer players performed SJ testing before each game of the fall season in addition to a baseline measurement at the start of preseason. The athletes provided sRPE values after all training sessions, weight-training, and games. Linear mixed modeling was used to compare changes in SJ height across the season with the baseline, and a correlation coefficient and single-lag cross-correlation coefficient were calculated between TL and changes in SJ height. No statistically significant decreases in SJ height occurred across the season, although a moderate practical decline occurred after the preseason (-1.6 cm, effect size = -0.70). The correlation between TL and changes in SJ height was statistically nonsignificant, whereas the cross-correlation was significant (r = 0.18, p = 0.48 and r = 0.55, p = 0.02, respectively). The athlete monitoring program was successful in managing the athletes' neuromuscular fatigue across the season as evidenced by the maintenance of SJ height and positive relationship between TL and changes in SJ height. Thus, SJ monitoring may serve as a useful fatigue monitoring tool for collegiate soccer athletes. Future study is needed, relating changes in vertical jump performance to other markers of athlete preparedness and performance.

Sole, CJ, Mizuguchi, S, Sato, K, Moir, GL, and Stone, MH. Phase characteristics of the countermovement jump force-time curve: a comparison of athletes by jumping ability. J Strength Cond Res 32(4): 1155-1165, 2018-The purpose of this study was to compare the phase characteristics of the countermovement jump (CMJ) force-time (F-t) curve between athletes based on jumping ability. An initial sample of one-hundred fifty Division-I collegiate athletes were ranked based on CMJ height. Three performance groups were then formed by taking the top, middle, and lower 30 athletes (15 men and 15 women) from the sample. Phases of the CMJ F-t curve were determined and then characterized by their duration, magnitude, area (impulse), and shape (shape factor). A series of 3-way mixed analysis of variance were used to determine statistical differences in phase characteristics between performance groups as well as between male and female athletes. Statistically significant phase-by-performance group interactions were observed for relative phase magnitude (p < 0.001), relative phase impulse (p < 0.001), and shape factor (p = 0.002). Phase-by-sex interactions were statistically significant for both relative phase magnitude (p < 0.001) and relative phase impulse (p < 0.001). Post hoc comparisons indicated that higher jumpers exhibited larger relative magnitude and impulse in the phases contained within the positive area of the F-t curve. Similarly, relative phase magnitude and impulse were the only phase characteristics to be statically different between men and women. Finally, the relative shape of the phase representing the initial rise in force was found to relate to jump height. These results provide some information regarding the diagnostic value of qualitative analysis of the CMJ F-t curve.

Kavanaugh, AA, Mizuguchi, S, Sands, WA, Ramsey, MW, and Stone, MH. Long-term changes in jump performance and maximum strength in a cohort of NCAA division I women's volleyball Athletes. J Strength Cond Res 32(1): 66-75, 2018-The purpose of this investigation was to quantify the magnitude of change in maximal strength and jumping abilities over approximately 1, 2, and 3 years of supervised sport and resistance training in National Collegiate Athletic Association (NCAA) division I women's volleyball athletes. This was an exploratory study on a cohort of women's volleyball athletes (n = 29) split into 3 groups based on the length of the time spent in a supervised resistance training program: group 1 (n = 11): 0.7 ± 0.3 years, group 2 (n = 9): 1.6 ± 0.2 years, and group 3 (n = 9): 2.4 ± 0.6 years. Monitoring tests consisted of standing height (cm), body mass (kg), body fat (%), static jump height (SJH) and countermovement JH (CMJH) with 0-, 11-, and 20-kg loads (cm), and midthigh clean pull isometric peak force (IPF) and allometrically scaled IPF (IPFa) (N·kg). Increasing trends were observed for all variables from groups 1 to 2 to 3. Statistically greater improvements (p ≤ 0.05) with moderate to large effect sizes were found between groups 1 and 3 for SJH 0 (19.7%, d = 1.35), SJH 11 (23.8%, d = 1.23), SJH 20 (30.6%, d = 1.20), CMJH 11 (22.6%, d = 1.18), IPF (44.4%, d = 1.22), and IPFa (41.2%, d = 1.32). A combination of traditional resistance training exercises and weightlifting variations at various loads, in addition to volleyball practice, seem to be effective at increasing maximal strength by 44% and vertical JH by 20-30% in NCAA division I women's volleyball athletes after about 2.5 years of training. Furthermore, these characteristics can be improved in the absence of additional plyometric training outside normal volleyball-specific practice.

Beckham, GK, Sato, K, Santana, HAP, Mizuguchi, S, Haff, GG, and Stone, MH. Effect of body position on force production during the isometric midthigh pull. J Strength Cond Res 32(1): 48-56, 2018-Various body positions have been used in the scientific literature when performing the isometric midthigh pull resulting in divergent results. We evaluated force production in the isometric midthigh pull in bent (125° knee and 125° hip angles) and upright (125° knee, 145° hip angle) positions in subjects with (>6 months) and without (

AS THE SPORT OF SURFING CONTINUES TO GAIN SUPPORT, THE NEED FOR A SOUND STRENGTH AND CONDITIONING PROGRAM IS PARAMOUNT. WITH A SEASON LASTING UPWARD OF 8 MONTHS AND TRAVELING ALL OVER THE WORLD, PROGRAMMING FOR THE SPORT OF SURFING QUICKLY BECOMES A CHALLENGE. THEREFORE, THE AIM OF THIS ARTI

Gleason, BH, Sams, M, Salley, JT, Pustina, A, and Stone, MH. Global positioning system analysis of a high school football scrimmage. J Strength Cond Res 31(8): 2183-2188, 2017-The purpose of this study was to examine the physical demands of a high school American football scrimmage. Male high school football players (N = 25) participated in a spring scrimmage. Global positioning system data and game film were recorded throughout the entirety of the scrimmage to determine the total distance covered, the distance covered in different velocity bands, the number of accelerations and decelerations performed, and the work-to-rest ratio of the scrimmage. The athletes were divided into 2 groups: linemen (L) (N = 7) vs. nonlinemen (NL) (N = 8) for statistical analysis, and independent T-tests with Holm's sequential Bonferroni adjustment were used to determine differences in movement characteristics between the L and NL groups. Average play duration was 5.7 ± 2.1 seconds, whereas the rest interval was 33.4 ± 13.6 seconds between plays, for an overall exercise-to-rest ratio of 1:5.9. Total distance, standing and walking distance, running distance, striding distance, sprinting distance, and total high-speed running distance covered by NL was greater than L (statistically significant at p ≤ 0.05). Distances traveled in each velocity band by position and by play are also included to provide context of our findings. Data from the present study add to the pool of support for the use of position-specific training in preparing high school football players for competition.

Stuart, CA, Lee, ML, South, MA, Howell, MEA, Cartwright, BM, Ramsey, MW, and Stone, MH. Pre-training muscle characteristics of subjects who are obese determine how well exercise training will improve their insulin responsiveness. J Strength Cond Res 31(3): 798-808, 2017-Only half of prediabetic subjects who are obese who underwent exercise training without weight loss increased their insulin responsiveness. We hypothesized that those who improved their insulin responsiveness might have pretraining characteristics favoring a positive response to exercise training. Thirty nondiabetic subjects who were obese volunteered for 8 weeks of either strength training or endurance training. During training, subjects increased their caloric intake to prevent weight loss. Insulin responsiveness by euglycemic clamps and muscle fiber composition, and expression of muscle key biochemical pathways were quantified. Positive responders initially had 52% higher intermediate muscle fibers (fiber type IIa) with 27% lower slow-twitch fibers (type I) and 23% lower expression of muscle insulin receptors. Whether after weight training or stationary bike training, positive responders' fiber type shifted away from type I and type IIa fibers to an increased proportion of type IIx fibers (fast twitch). Muscle insulin receptor expression and glucose transporter type 4 (GLUT4) expression increased in all trained subjects, but these moderate changes did not consistently translate to improvement in whole-body insulin responsiveness. Exercise training of previously sedentary subjects who are obese can result in muscle remodeling and increased expression of key elements of the insulin pathway, but in the absence of weight loss, insulin sensitivity improvement was modest and limited to about half of the participants. Our data suggest rather than responders being more fit, they may have been less fit, only catching up to the other half of subjects who are obese whose insulin responsiveness did not increase beyond their pretraining baseline.

This study examined and compared the acute effects of ballistic and nonballistic concentric-only half-squats (COHSs) on squat jump performance. Fifteen resistance-trained men performed a squat jump 2 minutes after a control protocol or 2 COHSs at 90% of their 1 repetition maximum (1RM) COHS performed in a ballistic or nonballistic manner. Jump height (JH), peak power (PP), and allometrically scaled peak power (PPa) were compared using three 3 × 2 repeated-measures analyses of variance. Statistically significant condition × time interaction effects existed for JH (p = 0.037), PP (p = 0.041), and PPa (p = 0.031). Post hoc analysis revealed that the ballistic condition produced statistically greater JH (p = 0.017 and p = 0.036), PP (p = 0.031 and p = 0.026), and PPa (p = 0.024 and p = 0.023) than the control and nonballistic conditions, respectively. Small effect sizes for JH, PP, and PPa existed during the ballistic condition (d = 0.28-0.44), whereas trivial effect sizes existed during the control (d = 0.0-0.18) and nonballistic (d = 0.0-0.17) conditions. Large statistically significant relationships existed between the JH potentiation response and the subject's relative back squat 1RM (r = 0.520; p = 0.047) and relative COHS 1RM (r = 0.569; p = 0.027) during the ballistic condition. In addition, large statistically significant relationship existed between JH potentiation response and the subject's relative back squat strength (r = 0.633; p = 0.011), whereas the moderate relationship with the subject's relative COHS strength trended toward significance (r = 0.483; p = 0.068). Ballistic COHS produced superior potentiation effects compared with COHS performed in a nonballistic manner. Relative strength may contribute to the elicited potentiation response after ballistic and nonballistic COHS.

The purpose of this study was to compare 4 methods that assess the lower-body stretch-shortening cycle (SSC) utilization of athletes. Eighty-six National Collegiate Athletic Association Division I athletes from 6 different sports performed 2 squat jumps and 2 countermovement jumps on a force platform. Pre-stretch augmentation percentage (PSAP), eccentric utilization ratio (EUR), and reactive strength (RS) for jump height (JH) and peak power (PP) magnitudes, and reactive strength index-modified (RSImod) were calculated for each team. A series of one-way analyses of variance with a Holm-Bonferroni sequential adjustment were used to compare differences in PSAP, EUR, RS, and RSImod between teams. Statistical differences in RSImod (p0.001) existed between teams, whereas no statistical differences in PSAP-JH (p = 0.150), PSAP-PP (p = 0.200), EUR-JH (p = 0.150), EUR-PP (p = 0.200), RS-JH (p = 0.031), or RS-PP (p = 0.381) were present. The relationships between PSAP, EUR, and RS measures were all statistically significant and ranged from strong to nearly perfect (r = 0.569-1.000), while most of the relationships between PSAP, EUR, and RS measures and RSImod were trivial to small (r = 0.192-0.282). Pre-stretch augmentation percentage and EUR, RS, and RSImod values indicate that women's tennis, men's soccer, and men's soccer teams may use the SSC most effectively, respectively. Pre-stretch augmentation percentage, EUR, RS, and RSImod values may show vastly different results when comparing an individual's and a team's ability to use the SSC. Practitioners should consider using RSImod to monitor the SSC utilization of athletes due to its timing component.

POWER-GENERATING CAPACITY SHOULD BE A PRIMARY TRAINING OUTCOME FOR FOOTBALL ATHLETES. THE ABILITY TO BE EXPLOSIVE AND USE HIGH LEVELS OF STRENGTH SEEMS TO DIFFERENTIATE BETWEEN ATHLETES AND TEAMS. DEVELOPING TRAINING INTERVENTIONS THAT CAN IMPROVE BOTH STRENGTH- AND POWER-GENERATING CAPACITY

This study sought to determine the level of association between bilateral force production symmetry assessment methods (standing weight distribution [WtD], unloaded and lightly loaded jumps, and isometric strength) and to determine whether the amount of symmetry carry-over between these tasks differs for strong and weak athletes. Subjects for this study included male (n = 31) and female (n = 32) athletes from National Collegiate Athletic Association Division I sports. Athletes performed WtD, unloaded and lightly loaded (20 kg) static and countermovement jumps, and isometric midthigh pull (IMTP) assessments on 2 adjacent force plates. Ground reaction force data were used to calculate symmetry variables and performance-related variables. Using Pearson zero order correlations, evaluations of the amount of symmetry carry-over were made. Weight distribution correlated strongly with jump peak force (PF) (r = 0.628-0.664). Strong relationships were also observed between loading conditions for jump variables (r = 0.568-0.957) as were the relationships between jump types for PF, peak power, and net impulse (r = 0.506-0.834). Based on the pooled sample, there was a lack of association between IMTP and WtD for jump symmetry variables. However, when examining strong and weak groups, rate of force development showed moderate to strong symmetry carry-over in the strongest athletes (r = 0.416-0.589). Stronger athletes appear to display similar explosive strength symmetry characteristics in dynamic and isometric assessments, unlike weaker athletes. Strength seems to influence the amount of force production symmetry carry-over between bilateral assessments. There may be optimal loads and variables for symmetry assessment, but these may differ based on population characteristics.

Athlete recovery-adaptation is crucial to the progress and performance of highly trained athletes. The purpose of this study was to assess peristaltic pulse dynamic compression (PPDC) in reducing short-term pressure-to-pain threshold (PPT) among Olympic Training Center athletes after morning training. Muscular tenderness and stiffness are common symptoms of fatigue and exercise-induced muscle microtrauma and edema. Twenty-four highly trained athletes (men = 12 and women = 12) volunteered to participate in this study. The athletes were randomly assigned to experimental (n = 12) and control (n = 12) groups. Pressure-to-pain threshold measurements were conducted with a manual algometer on 3 lower extremity muscles. Experimental group athletes underwent PPDC on both legs through computer-controlled circumferential inflated leggings that used a peristaltic-like pressure pattern from feet to groin. Pressures in each cell were set to factory defaults. Treatment time was 15 minutes. The control group performed the same procedures except that the inflation pump to the leggings was off. The experimental timeline included a morning training session, followed by a PPT pretest, treatment application (PPDC or control), an immediate post-test (PPT), and a delayed post-test (PPT) after the afternoon practice session. Difference score results showed that the experimental group's PPT threshold improved after PPDC treatment immediately and persisted the remainder of the day after afternoon practice. The control group showed no statistical change. We conclude that PPDC is a promising means of accelerating and enhancing recovery after the normal aggressive training that occurs in Olympic and aspiring Olympic athletes.

THE PURPOSE OF THIS REVIEW IS TWOFOLD: TO ELUCIDATE THE UTILITY OF RESISTANCE TRAINING FOR ENDURANCE ATHLETES, AND PROVIDE THE PRACTITIONER WITH EVIDENCED-BASED PERIODIZATION STRATEGIES FOR CONCURRENT STRENGTH AND ENDURANCE TRAINING IN ATHLETIC POPULATIONS. BOTH LOW-INTENSITY EXERCISE ENDURA

Sands, WA, Murray, MB, Murray, SR, McNeal, JR, Mizuguchi, S, Sato, K, and Stone, MH. Peristaltic pulse dynamic compression of the lower extremity enhances flexibility. J Strength Cond Res 28(4): 1058‐1064, 2014—This study investigated the effects of peristaltic pulse dynamic compression (PPDC) on range-ofmotion (ROM) changes in forward splits. Serious stretching usually involves discomfort and large time investments. Tissue structural changes and stretch tolerance have heretofore been considered the primary mechanisms of enhanced ROM. The PPDC treatment was computer controlled. Circumferential and segmented inflation pressures were induced by feet to hip leggings. Nine subjects, experienced in stretching and a forward split position, volunteered. The subjects were familiarized with the protocol and randomly assigned to an initial condition: experimental (PPDC), or control (CONT). The study involved a crossover design. Second conditions were tested within 1‐5 days. All tests were 2 trials of right and left forward splits. Split flexibility was assessed by measuring the height of the anterior superior iliac spine of the rear leg from the floor. Pelvic posture was controlled by rear leg position. The PPDC treatment was 15 minutes of seated PPDC. The control condition was the same except that leggings were not inflated. Pressures of 5 cells in the leggings were set at factory defaults, 70 mm Hg sequentially. Difference score results indicated statistically significant (p # 0.05) differences by condition and the condition by leg interaction. The rapid acute changes in ROM (PPDC: right 25.3%, left 33.3%; CONT: right 12.2%, left 1.0%) support the premise that changes in ROM were dependent on mechanisms other than tissue structural changes and/or stretch tolerance. PPDC provides a means of rapidly enhancing acute ROM requiring less discomfort and time.

This study analyzed the top 3 successful snatch attempts by individual lifters in each weight class at a U.S. National Championship weightlifting meet. Two-dimensional (2-D) body position and characteristics of the lifts were compared via 2D video analysis in groups of lifters who displaced forward, showed no displacement, or displaced backward to receive the bar. No significant group differences (p > 0.05) were noted for body mass, bar mass, or hip angle. The rearward displacement group had a significantly greater horizontal distance between the shoulder and heel at the end of the pull (determined as the point where the bar ceases to accelerate vertically). Hip angles for the no displacement group had a small-to-moderate effect size (0.50) in comparison to the forward displacement group, but they only showed a small effect size (0.17) when compared with the rearward displacement group. The forward displacement group showed a small-to-moderate effect size compared with both the no displacement group (0.51) and the rearward displacement group (0.55) concerning the horizontal distance from the shoulder to the heel. These data seem to suggest that rearward displacement in the drop-under phase in the snatch is not detrimental to performance and actually seems to be a preferred technique in U.S. national level lifters. In addition to evidence that rearward displacement is exhibited in elite lifters and is coached globally, it seems this is the preferred technique in international competitions. This technique may be considered a viable variation of the snatch by coaches and athletes of all levels.

STRETCHING IS A COMMONLY PRESCRIBED EXERCISE ACTIVITY THAT HAS BEEN APPLIED TO WARM-UP, INCREASING RANGE OF MOTION (ROM), AND RECOVERY FROM TRAINING. THE PRACTITIONER SHOULD UNDERSTAND THE EFFECTS OF STRETCHING EXERCISE AND THE INHERENT DIFFERENCES BETWEEN TYPES OF STRETCHING EXERCISES AND A

Limited research exists examining the effect of moderately loaded conditioning activities that are employed as part of a strength-power potentiating complex (SPPC). Additionally, no studies to date have explored the effects of using a concentric-only quarter back squat protocol as part of an SPPC. Therefore, the purpose of this study was to examine the effects of a moderately loaded (50-65% of 1RM) concentric-only quarter back squat protocol on the occurrence of potentiation effects at various time points. Twenty men who could quarter back squat a minimum of 2.4 times their body mass (3.7 ± 0.7 kg·per body mass) participated in this investigation. All subjects participated in 3 conditions: control (CT), a 50% of 1RM trial (50POT), and a 65% of 1RM trial (65POT). One minute before each condition, a maximal countermovement vertical jump (CMJ) was performed. One minute later, the subject performed 1 of 3 conditions: CT condition, 50POT, or 65POT, followed by vertical jumps at 0.5, 3, 5, 10, and 15 minutes after conditioning activity. A force plate was used to quantify displacement, peak power output, peak force, and the rate of force development for each CMJ. There were no significant differences (p > 0.05) in any of the performance measures quantified during the CMJ trials when comparing the CT, 50POT, and 65POT treatment conditions. However, 48% of the subjects demonstrated some degree of potentiation at the 30 seconds after completing the 65POT trial, but this percent increase was not statistically significant. From a practical perspective, if the goal of the SPPC is to create a maximization of the potentiation effect, moderately loaded activities may not be the best alternative.

RECENTLY, THE BODY MASS OF COLLEGE FOOTBALL LINEMAN HAS INCREASED MARKEDLY AND PLACES THEM AT HIGHER RISK FOR A NUMBER OF POSTCOMPETITIVE PATHOGENIC CHRONIC HEALTH CONSEQUENCES. RECOGNITION OF PROBLEMS ASSOCIATED WITH OVERSIZED ATHLETES IS EASILY ACCEPTED INTELLECTUALLY-HOWEVER, THE PRACTICALITIES OF SOLVING THE PROBLEM HAVE NOT BEEN FULLY REALIZED.

Purpose: To determine whether cycle training of sedentary subjects would increase the expression of the principle muscle glucose transporters, six volunteers completed 6 wk of progressively increasing intensity stationary cycle cycling. Methods: In vastus lateralis muscle biopsies, changes in expression of GLUT1, GLUT4, GLUT5, and GLUT12 were compared using quantitative immunoblots with specific protein standards. Regulatory pathway components were evaluated by immunoblots of muscle homogenates and immunohistochemistry of microscopic sections. Results: GLUT1 was unchanged, GLUT4 increased 66%, GLUT12 increased 104%, and GLUT5 decreased 72%. A mitochondrial marker (cytochrome c) and regulators of mitochondrial biogenesis (peroxisome proliferator-activated receptor [gamma] coactivator 1 [alpha] and phospho-5'-adenosine monophosphate-activated protein kinase) were unchanged, but the muscle hypertrophy pathway component, phospho-mammalian target of rapamycin (mTOR), increased 83% after the exercise program. In baseline biopsies, GLUT4 by immunohistochemical techniques was 37% greater in Type I (slow twitch, red) muscle fibers, but the exercise training increased GLUT4 expression in Type II (fast twitch, white) fibers by 50%, achieving parity with the Type I fibers. Baseline phospho-mTOR expression was 50% higher in Type II fibers and increased more in Type II fibers (62%) with training but also increased in Type I fibers (34%). Conclusion: Progressive intensity stationary cycle training of previously sedentary subjects increased muscle insulin-responsive glucose transporters (GLUT4 and GLUT12) and decreased the fructose transporter (GLUT5). The increase in GLUT4 occurred primarily in Type II muscle fibers, and this coincided with activation of the mTOR muscle hypertrophy pathway. There was little impact on Type I fiber GLUT4 expression and no evidence of change in mitochondrial biogenesis

THE INTRODUCTION OF NOVEL TRAINING STIMULI PLAYS A CRUCIAL ROLE IN INDUCING SPECIFIC TRAINING ADAPTATIONS. ONE METHOD THAT CAN BE EMPLOYED TO INTRODUCE A NOVEL STIMULUS TO THE TRAINING PROGRAM WHILE MAXIMIZING THE VELOCITY AND POWER OUTPUT OF THE TRAINING EXERCISE IS THE INCLUSION OF THE CLUSTER SET CONFIGURATION. THE CURRENT REVIEW PRESENTS THE THEORETICAL AND RESEARCH FOUNDATION FOR THE USE OF THE CLUSTER SET IN PERIODIZED TRAINING PROGRAMS AND OFFERS EXAMPLES OF PRACTICAL APPLICATIONS THAT CAN BE USED IN THE PREPARATION OF ATHLETES IN A VARIETY OF SPORTS.

Purpose: Effects of simultaneous vibration-stretching on flexibility and explosive strength in competitive female gymnasts were examined. Methods: Twenty-two female athletes (age = 11.3 ± 2.6 yr; body mass = 35.3 ± 11.6 kg; competitive levels = 3-9) composed the simultaneous vibration-stretching (VS) group, which performed both tests. Flexibility testing control groups were stretching-only (SF) (N = 7) and vibration-only (VF) (N = 8). Explosive strength-control groups were stretching-only (SES) (N = 8) and vibration-only (VES) (N = 7). Vibration (30 Hz, 2-mm displacement) was applied to four sites, four times for 10 s, with 5 s of rest in between. Right and left forward-split (RFS and LFS) flexibility was measured by the distance between the ground and the anterior suprailiac spine. A force plate (sampling rate, 1000 Hz) recorded countermovement and static jump characteristics. Explosive strength variables included flight time, jump height, peak force, instantaneous forces, and rates of force development. Data were analyzed using Bonferroni adjusted paired t-tests. Results: VS had statistically increased flexibility (P) and large effect sizes (d) in both the RFS (P = 1.28 × 10-7, d = 0.67) and LFS (P = 2.35 × 10-7, d = 0.72). VS had statistically different results of favored (FL) (P = 4.67 × 10-8, d= 0.78) and nonfavored (NFL) (P = 7.97 × 10-10, d = 0.65) legs. VF resulted in statistical increases in flexibility and medium d on RFS (P = 6.98 × 10-3, d = 0.25) and statistically increased flexibility on VF NFL flexibility (P = 0.002, d = 0.31). SF had no statistical difference between measures and small d. For explosive strength, there were no statistical differences in variables in the VS, SES, and VES for the pre- versus posttreatment tests. Conclusions: Simultaneous vibration and stretching may greatly increase flexibility while not altering explosive strength

Glaister, M., M.H. Stone, A.M. Stewart, M.G. Hughes, G.L. Moir. Aerobic and anaerobic correlates of multiple sprint cycling performance. J. Strength Cond. Res. 20(4):792- 798. 2006.-The aims of this study were to examine (a) the relationship between maximal oxygen uptake ( O2max) and several performance indices of multiple sprint cycling; (b) the relationship between maximal accumulated oxygen deficit (MAOD) and those same performance indices; and (c) the influence of recovery duration on the magnitude of those relationships. Twenty-five physically active men completed a O2max test, a MAOD test, and 2 maximal intermittent (20 × 5 seconds) sprint cycling tests with contrasting recovery periods (10 seconds or 30 seconds). Mean ± SD for age, height, and body mass were 20.6 ± 1.5 years, 177.2 ± 5.4 cm, and 78.2 ± 8.2 kg, respectively. All tests were conducted on a friction-braked cycle ergometer with subsequent data normalized for body mass. Moderate (0.3 r < 0.5) positive correlations were observed between power output data and MAOD (range, 0.31-0.46; 95% confidence limits, ?0.10 to 0.72). Moderate to large positive correlations also were observed between power output data and O2max, the magnitude of which increased as values were averaged across all sprints (range, 0.45-0.67; 95% confidence limits 0.07-0.84). Correlations between fatigue and O2max were greater in the intermittent protocol with 30-second recovery periods (r = ?0.34; 95% confidence limits, 0.06 to ?0.65). The results of this study reflect the complex energetics associated with multiple sprint work. Though the findings add support to the idea that multiple sprint sports demand a combination of speed and endurance, further longitudinal research is required to confirm the relative importance of these parameters.

Eight male collegiate weightlifters (age: 21.2 +/- 0.9 years; height: 177.6 +/- 2.3 cm; and body mass: 85.1 +/- 3.3 kg) participated in this study to compare isometric to dynamic force-time dependent variables. Subjects performed the isometric and dynamic mid-thigh clean pulls at 30-120% of their one repetition maximum (1RM) power clean (118.4 +/- 5.5 kg) on a 61 x 121.9-cm AMTI forceplate. Variables such as peak force (PF) and peak rate of force development (PRFD) were calculated and were compared between isometric and dynamic conditions. The relationships between force-time dependent variables and vertical jump performances also were examined. The data indicate that the isometric PF had no significant correlations with the dynamic PF against light loads. On the one hand, there was a general trend toward stronger relationships between the isometric and dynamic PF as the external load increased for dynamic muscle actions. On the other hand, the isometric and dynamic PRFD had no significant correlations regardless of the external load used for dynamic testing. In addition, the isometric PF and dynamic PRFD were shown to be strongly correlated with vertical jump performances, whereas the isometric PRFD and dynamic PF had no significant correlations with vertical jump performances. In conclusion, it appears that the isometric and dynamic measures of force-time curve characteristics represent relatively specific qualities, especially when dynamic testing involves small external loads. Additionally, the results suggest that athletes who possess greater isometric maximum strength and dynamic explosive strength tend to be able to jump higher.

This is the second part of a 2-part discussion (the first,"Weightlifting: A Brief Overview," appeared 28(1):50-66, 2006) on weightlifting and will describe the best methods of designing a weightlifting program

SANDS, W. A., J. R. MCNEAL, M. H. STONE, E. M. RUSSELL, and M. JEMNI. Flexibility Enhancement with Vibration: Acute and Long-Term. Med. Sci. Sports Exerc., Vol. 38, No. 4, pp. 720–725, 2006. Introduction: The most popular method of stretching is static stretching. Vibration may provide a means of enhancing range of motion beyond that of static stretching alone. Purpose: This study sought to observe the effects of vibration on static stretching to determine whether vibration-aided static stretching could enhance range of motion acquisition more than static stretching alone in the forward split position. Methods: Ten highly trained male volunteer gymnasts were randomly assigned to experimental (N = 5) and control (N = 5) groups. The test was a forward split with the rear knee flexed to prevent pelvic misalignment. Height of the anterior iliac spine of the pelvis was measured at the lowest split position. Athletes stretched forward and rearward legs to the point of discomfort for 10 s followed by 5 s of rest, repeated four times on each leg and split position (4 min total). The experimental group stretched with the device turned on; the control group stretched with the device turned off. A pretest was followed by an acute phase posttest, then a second posttest measurement was performed following 4 wk of treatment. Difference scores were analyzed. Results: The acute phase showed dramatic increases in forward split flexibility for both legs (P G 0.05), whereas the long-term test showed a statistically significant increase in range of motion on the right rear leg split only (P G 0.05). Effect sizes indicated large effects in all cases. Conclusion: This study showed that vibration can be a promising means of increasing range of motion beyond that obtained with static stretching in

The primary objective of this study was to analyze the relationship between testosterone levels and vertical jumping performance in elite men and women athletes. The secondary objective was to verify whether testosterone levels and vertical jumping performance were different in men and women athletes and if those measurements were different between different athletic groups. Seventy (22 women and 48 men) elite athletes in track and field (sprinters), handball, volleyball, and soccer competing at national and international levels participated in the study. After 10 hours of fasting and 1 day of rest, blood samples were drawn from the antecubital vein for determining testosterone levels. Vertical jumping tests consisted of countermovement jumps conducted on a resistive platform connected to a digital timer. Resting testosterone levels in women were 9.5% of those of the men (respectively 0.62 +/- 0.06 ng.ml(-1) and 6.49 +/- 0.37 ng.ml(-1); p < 0.001). Countermovement jump performance was significantly different between women and men athletes, with women's jumping ability 86.3% of that of men (p < 0.001). A significant positive relationship was identified between testosterone levels and vertical jump performance when all data where considered (r = 0.61, p < 0.001, n = 70).

summaryWeightlifting exercises can be effective for enhancing athletic performance. This article provides a biomechanical and physiological discussion as to why weightlifting exercises are useful to improve athletic performance and how they may be integrated into a training program.

Objectives: Pre-participation examination, screening and health surveillance are part of the job specification for many roles within Sports Medicine. The type and scope of this activity varies enormously, with little consensus as to best evidence-based practice. The purpose of this work was to explore and understand the practical approaches to pre-participation examination, screening and health surveillance in two contrasting sport scenarios. Data Source: Team physicians for British Triathlon and Manchester United Football Club. Data synthesis/Methods: Information was gathered under the headings: why screen, screening objectives, practical issues and constraints? Results: The systems evolved within these two sports reflect their respective opportunities and constraints. Different systems, each with merit, have evolved with some generalizable concepts across sport. Conclusions: A perfect system for pre-participation examination, screening and health surveillance across all sport does not exist, however, within specific sport scenarios examples of good practice are demonstrated.

The purpose of the present study was to determine the number of familiarization sessions required to obtain an accurate measure of reliability associated with loaded vertical jump and 20-m sprint running performance. Ten physically active men attended 5 separate testing sessions over a 3-week period where they performed unloaded and loaded (10-kg extra load) countermovement (CMJ) and static (SJ) jumps, followed by straight-line 20-m sprints. Jump height was recorded for the vertical jumps using a jump mat, while the time for 10 m and 20 m was recorded during the sprints using photocells. The highest (jump conditions) and fastest (sprint) of 3 trials performed during each of the 5 testing sessions was used in the subsequent analysis. Familiarization was assessed using the scores obtained during the 5 separate testing sessions. Reliability was assessed by calculating intraclass correlation coefficients (ICCs) and coefficient of variation (CV). No significant differences were obtained between the testing sessions for any of the measures. ICCs ranged from 0.89 to 0.95, while CVs ranged from 1.9 to 2.6%. These results indicate that high levels of reliability can be achieved without the need for familiarization sessions when using loaded and unloaded CMJ and SJ and 20-m sprint performance with physically active men.

The effect of 3 warm-up routines on standing broad jump (SBJ) performance was investigated. Thirty-two men and women participated as subjects. Following the determination of 1-repetition maximum (1RM) squat, subjects completed warm-up routines and broad jumps on 4 occasions in a randomized order. Subjects performed SBJ immediately (POST) and 15 min following (POST15) the given warm-up routine. The routines were high force, consisting of high % 1RM, low repetition squats; high power, consisting of low % 1RM, low repetition speed squats; stretching, consisting of static stretches; and no activity, a control condition. Repeated measures analysis of covariance (ANCOVA) revealed no differences among broad jump performance following any of the warm-up routines (p = 0.157). A strong correlation (R = 0.805) was found between 1RM squat and SBJ. These data indicate that warm-up of any type has little effect on jump performance and that maximum strength is strongly related to jumping ability.