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It is well accepted within the culture of collision-based team-sports such as football and rugby that resistance training is a key component to physical preparation. Most teams will include some form of resistance training during both the preparatory and competitive season. While little debate surrounds the usefulness of strength training for these athletes, many coaches still debate which periodization scheme is superior for inducing physical and performance changes. Linear periodization is the traditional approach that progresses athletes from phases of high volume and low intensity to low volume and high intensity over a period of months. Undulating periodization, popularized by former Olympic strength coach Charles Poliquin, emphasizes both high and low volumes and intensities within a given microcycle. Both training methodologies have been shown to enhance strength and performance, however it remains unclear which is superior.

A new study published ahead of print in the Journal of Strength and Conditioning Research compared the effects of traditional versus undulating periodization on performance markers in a group of high-level adolescent male rugby players. A sample of twenty-six, 16-17 year old rugby players were randomly allocated to a traditional periodization group (n=8), an undulating periodization group (n=8) or a control group (n=10). For a period of 12 weeks, all groups participated in their normal rugby training twice per week. The training groups performed an additional 2 resistance training sessions per week over the 12-week period. While the training programs differed in structure according to the periodization scheme, overall volume and intensity did not significantly differ between groups. Before and after the training program, 10 and 20 m sprint time and vertical jump height (unloaded and loaded 10 kg) were tested as markers of performance.

The results showed that 1RM box-squat strength improved by 33.9% for the traditional group and 44.5% for the undulating group (effect sizes ranging from large to very large). Improvements (i.e., reductions) in 10 m and 20 m sprint time were -1.6% and -0.5%, respectively, for the traditional group and -2.5% and -1.7%, respectively, for the undulating group (all effect sizes were small). Only the traditional group showed improvements in the unloaded vertical jump (4.3%) while only  the undulating group showed improvements in the loaded vertical jump (7.5%). Small to moderate correlations were observed between changes in lower body absolute and relative strength with changes in 10 and 20 m sprint times. Overall, undulating periodization appears to have resulted in superior changes in strength and performance among adolescent rugby players, although traditional periodization was also effective.

 

Reference:

Harries, SK. et al. Effects of 12-weeks resistance training on sprint and jump performance in competitive adolescent rugby union players. J Str Cond Res. In Press.

When coaches think of an intervention to enhance physical performance in their athletes, they would most often come up with some type of “sport-specific” workout regiment or various technical or tactical drills. Certainly, these types of interventions can absolutely result in meaningful performance improvements. However, there may be some more passive interventions that coaches can implement with their teams that may have a much more profound effect on performance than they would have originally thought. The concept of sleep extension, or increasing sleep duration time to improve performance seems obvious. But just how much can increasing sleep time affect performance? And how long should we be encouraging our athletes to sleep to derive the performance enhancing benefits?

A recent study from the Stanford Sleep Clinic was published in the journal “Sleep” and investigates the impact of sleep extension on physical and technical performance markers in athletes. A sample of 11 NCAA collegiate basketball players from the Stanford University men’s basketball team volunteered as participants. For a 2-4 week period, baseline sleep characteristics were monitored to determine typical sleep and wake times, sleep duration, etc. Following baseline, all subjects participated in a 5-7 week sleep extension period where they were given a goal of staying in bed for a minimum of 10 hours each night. Athletic performance variables including sprinting speed, shooting accuracy (free-throws and 3-point shot attempts), reaction time, levels of daytime sleepiness and overall mood were monitored throughout the study period.

The results showed that total objective sleep time significantly increased during the intervention period by an average of nearly 2 hours. In addition, sprint times demonstrated a significant improvement following sleep extension (4.5% average reduction in sprint time). Both free-throw and 3-point shot accuracy significantly improved by 9% and 9.2%, respectively. Significant improvements were also observed for reaction time and perceptions of daytime sleepiness (both decreased). Other subjective indicators also improved, including increased vigor, decreased fatigue and overall improvements in mental and physical well-being during training and competition. The authors conclude that increasing sleep duration may be a key factor for optimizing athletic performance in basketball players.

Reference:

Cheri D. Mah, MS, Kenneth E. Mah, MD, MS, Eric J. Kezirian, MD, MPH, William C. Dement, MD, PhD; The Effects of Sleep Extension on the Athletic Performance of Collegiate Basketball Players. Sleep 2011; 34 (7): 943-950. doi: 10.5665/SLEEP.1132

 

 

The glute-ham-gastroc raise, or one of its derivatives (i.e., the nordic hamstring curl) are commonly used among sports teams as a means of reducing hamstring injury risk. This is because the hamstrings are frequently injured during bouts of maximal sprinting in training or competition. Therefore, the glute-ham-gastroc raise is most often perceived as an “injury prevention” type movement as opposed to one that can improve performance. The gastroc muscles play a fundamental role in athletic movements (e.g., various jumping tasks) in both force production and force absorption. Traditional weight-room exercises such as cleans and squats may not adequately develop the gastrocs and thus fail to maximize performance on the field. Whether incorporation of glute-ham-gastroc raise has any meaningful effect on indicators of performance remains unclear.

A new study published ahead of print in the Journal of Strength and Conditioning Research evaluated the effects of supplementing a traditional resistance training program with (or without) incorporation of the glute-ham-gastroc raise on indices of performance. A group of twenty-three, 16-18 year-old female volleyball players with minimal resistance training experience were randomly split into a control group (n = 12) and an experimental group (n=11). Both groups performed an 8-week periodized full-body resistance training program  with emphasis on the front squat and clean. The only difference between groups was that the experimental group performed glute-ham-gastroc raises within their program. Before and after the training period, all players were tested in vertical jumping ability (with and without step approach), weight-bearing ankle dorsiflexion and jump propulsion and landing mechanics.

The results showed that the experimental group improved both approach and standing vertical jump height by 44% and 69%, respectively, more than the control group. The effect sizes regarding changes in jump performances were rated as “small” for the control group and “moderate” for the experimental group. Weight-bearing dorsiflexion for right and left ankles among the experimental group improved 65% and 193%,  respectively, more than the control group. Minimal differences in jump propulsion and landing mechanics were observed among either group. The authors conclude that incorporating the glute-ham-gastroc exercise may have a beneficial effect with young female volleyball players on jumping performance and angle range of motion when added to traditional resistance training.

Reference:

Chiu, L. Z., & Yaremko, A. (2017). Addition of Glute-Ham-Gastroc Raise to a Resistance Training Program: Effect on Jump Propulsion and Landing. The Journal of Strength & Conditioning Research. In Press.

 

As the topic of post-activation continues to receive greater attention among coaches and researchers, teams are experimenting with a variety of pre-training resistance training bouts in an effort to acutely enhance performance. One of the variables that remains unclear in the literature is the optimal load that athletes should use to induce a meaningful effect on game-performance parameters, such as repeated sprinting ability. For example, performing barbell back squats with light to moderate loads allows the athlete to perform a greater number of repetitions at a higher propulsive velocity. Theoretically, this may result in increased contraction velocity during subsequent athletic tasks. On the other hand, performing the same exercise with heavy loads forces the athlete to perform fewer repetitions at a lower propulsive velocity. This may result in greater force production on the field. Which method is superior?

A new study published ahead of print in the Journal of Human Kinetics evaluated the effects of two different post-activation potentiation protocols on athletic performance variables in national and regional level soccer players. A total of sixteen soccer players (8 from each level), approximately 20 years of age participated in the study. On three occasions, all subjects performed a repeated sprint ability test (6 x 20 m sprints with 20 s of recovery between reps) preceded by a) a control condition, b) squatting with 60% of 1RM allowing for a mean concentric velocity of 1.0 m/s and c) squatting with 90% of 1RM allowing for a mean concentric velocity of 0.5 m/s. The testing order was randomized and separated by several days. Peak and mean running speed was recorded for each athlete during the repeated sprint test.

The results showed that squatting with 90% of 1RM loads prior to the test resulted in large improvements in both peak and mean sprinting speed among the national level players but only a small improvement for regional players. Comparing all sprints between groups, the national level players had consistently greater improvements in sprinting speed following the heavy squatting protocol (90% of 1RM). The 60% of 1RM squat protocol provoked minimal changes in repeated sprint performance among groups. These results indicate that incorporating heavy squats within the warm-up protocol can meaningfully improve repeated sprint performance in national level soccer players uand

Reference:

Sanchez, J. Effects of different post-activation potentiation warm-ups on repeated sprint ability in soccer players from different competitive levels. Journal of Human Kinetics. In Press.

Speed can be a determining factor in any team-sport competition. This is why many coaches dedicate considerable time and effort into improving speed. Resisted sprint-training is a traditional means of speed development in athletes. One of the most effective and popular methods of implementing resisted sprint-training is via sled-towing. However, considerable debate surrounds optimal training strategies for this practice. For example, whether sled loads should be light (e.g., <10% of athletes body mass) or heavy remains to be determined. In addition, when using sled towing as a means of inducing post-activation potentiation to enhance subsequent sprint efforts, the optimal rest-time between towing and free-sprinting is unclear.

A new study published in the latest issue of the Journal of Trainology evaluated the acute effects of heavy sled towing on subsequent sprint acceleration performance. A sample of eight collegiate male athletes performed three different sprint protocols on different days, separated by at least 72 hours in randomized order. Protocol 1 consisted of 1 set of sled-towing over 15 m with 50% of body mass; protocol 2 consisted of 2 sets of sled-towing over 15 m with 50% of body mass and; protocol 3 consisted of 3 sets of sled-towing over 15 m with 50% of body mass. Inter-set rest periods were 90 seconds. Four minutes prior to each protocol, an unload 15 m sprint was evaluated via electronic timing gates to serve as baseline. Following each protocol, 15 m sprint time was tested at 4, 8 and 12 minutes post-sled-towing.

The results of this study showed that protocol 3 (3 sets of sled-towing with 50% of body mass) after 8 minutes of rest produced significantly faster 15 m sprint times compared to baseline sprint-speed (average improvement of 0.07, p <0.05, effect size = small). All individual subjects ran their fastest 15 m time following 8 or 12 minutes of rest. The authors conclude that performing maximal effort sled-towing with 50% of body mass for 3 sets transiently enhances sprinting speed when at least 8 minutes of rest are provided following the sled-towing protocol. Thus, coaches can implement heavy sled-towing to induce post-activation potentiation, but must be mindful of allowing adequate rest before unloaded sprinting to derive performance enhancing effects.

Reference:

Jarvis, P. et al. The acute effects of heavy sled towing on subsequent sprint acceleration performance. Journal of Trainology. 2017;6:18-25.

 

The warm-up protocol used before training and competition is often taken for granted and the time allotted may not be used optimally by coaches. Increasing body temperature and ensuring that various movements are performed in each plane and through a full-range of motion is important for reducing the risk of injury. However, typical activities performed during the warm-up such as jogging, side-shuffling and dynamic stretches may not cut it for optimizing performance potential. Coaches who are familiar with post-activation potentiation are aware that force production and rate of force development can be enhanced with certain exercises. Therefore, strategically implementing potentiating movements in the warm-up may lead to subsequent enhanced performance of explosive actions like sprinting and jumping. However, timing likely plays an important role in the effectiveness of such a strategy as waiting too long may result in loss of potentiation effects.

A new study published ahead of print in the Journal of Strength and Conditioning Research aimed to determine the potentiating effects of drop-jumps incorporated into the warm-up routine on the time-course of changes in lower body strength and power. A group of 20 collegiate athletes performed both an experimental warm-up that included 2 sets of 5 drop jumps (15 s between repetitions and 3 min between sets) and a control warm-up (walking). The protocol order was randomized and separated by at least 72 hours. To evaluate whether the experimental condition impacted lower body performance potential, electrically-evoked isometric muscle twitches were recorded throughout each protocol to measure peak twitch torque, rate of force development, amplitude and impulse.

The results showed that the warm-up protocol involving drop-jumps significantly increased peak twitch torque (23%), rate of force development (39%) and impulse (46%) while these parameters were significantly reduced following the control protocol. Interestingly, there was no change observed in amplitude which the researchers interpreted as evidence that that augmented torque was due to post-activation potentiation. Regarding the time-course factor, the researchers found that the potentiation effects returned to baseline within 6 minutes of the drop-jumps and trended below baseline within 15 minutes. Thus, it was concluded that drop-jumps acutely enhance muscle force generating capacity and that they should be implemented immediately before competition to take advantage.

Reference:

Johnson, M., Baudin, J. P., Ley, A. L., & Collins, D. F. (2017). A warm-up routine that incorporates a plyometric protocol potentiates the force generating capacity of the quadriceps muscles. The Journal of Strength & Conditioning Research.

The sport of soccer is traditionally thought of as a predominantly aerobic-endurance sport. This is because matches can last in excess of 1.5 hours in addition to involving a considerable amount of jogging and walking between short bursts. For these reasons, many soccer coaches are concerned primarily with developing cardiorespiratory fitness among their players and are less concerned with developing lower-body muscular power. However, neglecting explosive training in favor of long, slow-distance steady state running can be counterproductive. Many critical moments in a soccer matches come down to explosive actions such as sprinting for an open ball or jumping to make a header off of a cross. These types of actions are not uncommon during soccer matches and players must possess a sufficient amount of lower body maximal strength and power to be effective during those situations.

A new study published ahead of print in the Journal of Strength and Conditioning Research sought to determine if lower-body explosive power could discriminate starters from non-starters in a team of Division-1 women’s soccer players. Eight-teen college-aged players were categorized as starters or non-starters based on total minutes played and number of games started from the previous competitive season. Prior to the start of the off-season strength and conditioning program, all players underwent maximal squat-jump testing to assess lower-body muscular power. Each athlete was given 3 squat-jump attempts with one minute of rest between attempts.  A linear position transducer was used to measure squat-jump height, mean velocity, peak velocity, mean power, peak power from each squat-jump attempt. All values were then compared between starters and non-starters.

The results showed that mean power and peak power values between starters and non-starters were not statistically different (p = 0.093 and 0.097, respectively), however the effect sizes indicated that these values were moderately higher for the starters (ES = 90 and 0.94, respectively). Squat-jump height, mean velocity and peak velocity were all significantly higher in the starters compared with the non-starters and the effect sizes were all large. Additionally, squat-jump height was significantly correlated with mean velocity (r = 0.63) and peak velocity (r = 0.65). Thus, these results demonstrate that markers of lower-body muscular power discriminate starters from non-starters in high-level female collegiate soccer players. Coaches should therefore consider emphasizing developing lower-body strength and power in their athletes.

Reference:

Magrini, M.A., et al. Distinguishing Playing Status Through a Functionally Relevant Performance Measure in Female Division I Collegiate Soccer Athletes. Journal of Strength and Conditioning Research, In press.

A common misconception regarding resistance training is that it is unsafe and ineffective for youth athletes. Provided that the training program is implemented and supervised by a qualified coach, the risk of injury is actually quite minimal. Additionally, while it is true that young athletes are unable to build substantial amounts of lean body mass from resistance training, other neurological adaptations can occur that may facilitate performance improvements. For example, young athletes can improve the recruitment and synchronization of motor units which can increase force production and rate of force development. This can transfer to increases in running, jumping and change of direction ability. However, many parents and coaches remain skeptical about having their young athletes participate in resistance training programs.

A new study published ahead of print in the Journal of Strength and Conditioning Research compared the effects of bodyweight training versus body weight plus additional resistance training on athletic performance measures in youth athletes. A total of 39 male athletes (~14 years of age) were randomly assigned to a bodyweight training group (n=25) a body weight plus resistance training group (n=14) while a group of age-matched boys (n=23) served as the control group. Over a 7-week period both training groups performed two bodyweight workouts per week. Of the training groups, only one performed resistance training on two additional days of the week on non-consecutive days. Before and after the training intervention, all subjects underwent testing in the vertical and horizontal jump, 5 and 20 m sprint, 2 kg medicine ball throw and maximal push-ups. The body weight program was comprised of various calisthenics as well as unilateral and bilateral exercises. The resistance training program involved multi-joint exercises such as squats, presses, deadlifts and rows for 2-3 sets of 5-15 repetitions with resistances ranging between 40-70%.

The results showed that the group that performed resistance training in addition to bodyweight training made the greatest improvements in 5 and 20 m sprint time (ES = Small), horizontal jump (ES = Small) and maximal number of push-ups (ES = Small). The bodyweight training only group meaningfully improved in the 5 m sprint, horizontal jump and push-ups (ES = Small) but to a lesser extent than the resistance training group. No groups meaningfully improved in the countermovement jump or medicine ball throw. This study demonstrates that resistance training twice per week for seven week offers superior performance benefits to calisthenics alone in youth male athletes.

Reference:

Winwood, P. W. (2017). Short Term Effects of Resistance Training Modalities on Performance Measures in Male Adolescents. The Journal of Strength & Conditioning Research. In press.

The topic of athlete monitoring has garnered a lot of attention from both coaches and sport scientists in recent years. This is partly due to a greater appreciation of the fact that individual training responses differ substantially among athletes. By tracking fatigue and recovery status, coaches can make strategic training interventions for individuals by increasing or reducing training loads, prescribing recovery modalities and so forth. One of the most common and useful monitoring variables that team-sport coaches track is neuromuscular function because of its strong involvement in athletic performance. The countermovement jump is often used as a key performance indicator for sports such as soccer, rugby and basketball because it is a convenient marker of lower body power. It’s hypothesized that a reduction in countermovement jump performance correlates with decrements in on field performance markers such as sprinting speed and distance coverage. However, research on this topic is quite limited.

A new study published ahead of print in the Journal of Strength and Conditioning Research sought to determine whether markers of lower body power and muscle damage predicted training outputs in elite male soccer players. Thirty players from an elite team performed a countermovement jump test and provided blood samples for creatine kinase analysis (a marker of muscle damage) prior to practice throughout a training period. During all training sessions, global positioning system (GPS) devices were worn by all players. The training outputs derived from GPS included total distance, sprint distance, high speed distance, accelerations, decelerations, explosive distance and maximal velocity.

The results showed significant main effects for both countermovement jump and creatine kinase Z-scores (normalized values). A reduction in countermovement jump performance by 1 Z-score resulted in decrements in various training outputs (total high speed distance, very high speed distance, accelerations, decelerations, explosive distance, and maximal velocity running) by an average of -2—       -5.6%. Similar decrements in training outputs for the same variables were observed with an increase in muscle damage corresponding to a Z-score increase of 1 for creatine kinase. These results suggest that pre-training countermovement jump scores may provide insight to coaches regarding performance potential in soccer players.

Reference:

Malone, S., et al. Decrements in neuromuscular performance and increases in creatine kinase impact training outputs in elite soccer players. Journal of Strength and Conditioning Research. In press.

As coaches, we have the responsibility of providing our athletes with the best opportunity to be successful on the field. We strive to optimize performance through training and nutritional interventions. In an athletes’ pursuit to constantly up their game, they will eventually be confronted with the option of using sport nutrition supplements. In this situation, the coach must consider (at least) 3 important questions concerning a given sport supplement product:

  1. Is it legal?
  2. Is it safe?
  3. Is it effective?

Being able to answer these questions should help the coach guide the athlete to making the most informed decision possible. A review of the available research will ultimately show that very few sport nutrition supplements can substantially improve performance. However, caffeine is one of the supplements that tends have a decent track record of success and its supplementation may be worth exploring.

In a new study published ahead of print in the International Journal of Sports Physiology and Performance, the effects of moderate doses of caffeine ingestion on countermovement jump performance was investigated. A group of 10 elite male volleyball players volunteered for this study. In a randomized, cross-over design, the athletes performed two trials of countermovement jumps on a force plate separated by one week, with or without caffeine. This was a double-blind study, meaning that neither the researchers nor the athletes knew at which trial they were given caffeine in an effort control for bias and placebo effects. Three countermovement jumps were performed following 60-min of placebo or caffeine (5 mg/kg) ingestion. At 24 hours post-trial, all subjects completed questionnaires regarding any potential side effects that may have encountered from the caffeine.

The results showed that caffeine ingestion resulted in significant increases in numerous markers of performance during the countermovement jump including peak concentric force output (6.4%), peak power (16.2%) flight time (5.3%), peak velocity (12.6%) and peak acceleration (13.5%). In addition, caffeine ingestion reduced the time between peak power and peak force (16.7%). Diastolic blood pressure increased by an average of 13% from caffeine ingestion and no adverse side effects were noted from the questionnaires. This study adds to the growing body of evidence demonstrating that caffeine intake may enhance neuromuscular performance in athletes.
Reference: Zbinden-Foncea, H. et al. Effects of Caffeine on Countermovement Jump Performance Variables in Elite Male Volleyball Players. International Journal of Sports Physiology and Performance. In press.