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marylin monroe
Showing posts with label burpees. Show all posts
Showing posts with label burpees. Show all posts

Exercise Research Update Nov '14 (1/2): Planking in Slings, Burpees for the Ultimate HIIT Experience, the Different Motors of Strength Gains in Young & Old Chaps + More!

There is a good reason drill-instructors love their burpees ;-)
Today's installment of the short news is a collection of shorter news items that deal with what's really important in life... well, maybe we should say some of the things that are really important in life: Building muscle, strength and a better physique.

That being said, we will take a look at the efficacy of sling-based planking, lean mass vs. neuromuscular efficacy as drivers of strength gains in young men and women and burpee-based high intensity interval training (HIIT) vs. classic ergometer / spinning based HIIT sessions and the changes the bodies of college students will undergo within one semester of conditioning training.
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  • Old vs. young - 1:1 for strength. Study shows similar increases in strength after short-term resistance training due to different neuromuscular adaptations in young and older Men... or put simply: The mechanisms by which the strength of the 23 young (29 ± 9 years) and 26 older men (64 ± 8 years) who completed 10 weeks of high-volume, medium load “hypertrophic” resistance training with low frequency (twice per week) with 10 young (34 ± 11 years) and 11 older men (65 ± 3 years) acting as nontraining control subjects, was different, the strength increase, on the other hand, was identical.

    More specifically, the training regimen led to significant increases in 1 repetition maximum (1RM) leg press performance in both training groups (young: 13 ± 7%, p < 0.001; older: 14 ± 9%, p < 0.001), who had been advised to consume ~20 g of protein within 1 hour of training and make sure to get a total ~1.5–1.8 g of protein per kg body mass per day, to optimize the muscle hypertrophy response.
    Figure 1: Lower-limb lean mass (upper left), vastus lateralis cross-sectional area (lower left), and voluntary activation level (lower right) before and after training in young and older men, as well as relationship between changes in 1RM performance and lower-limb lean mass during training in young men (upper right). ** p , 0.01 compared with before training. C = p # 0.05 compared with control group; YT = p # 0.05 compared with young training group (Walker. 2014).
    In that, the performance improvement, however, was accompanied by increased muscle activation, assessed by voluntary activation level (29 ± 51%, p ≤ 0.05) and electromyography amplitude (35 ± 51%, p < 0.01) in older men only. In the young men, on the other hand, the increase in strength was mediated by increases in lean mass (2.4 ± 2.5%, p < 0.01), not increased muscle activation.

    As Walker & Häkinnen point out, the study clearly indicated this form of "resistance training may induce similar improvements in strength between young and older men, it appears that different mechanisms underpin these improvements" (Walker. 2014)... unfortunately, for the old guys, their way of becoming stronger is very limited. In the end, continuous strength gains can only be achieved, when they are driven by skeletal muscle hypertrophy. Accordingly, the results would probably have looked much different, if the guys in the "old trainees" group had been resistance training and not endurance training regularly before.
  • Plank(ing) in slings is highly effective (edited). While conlusion of the abstract misleading says that Jeanette Byrne et al. (2014) didn't find an increase in the abdominal muscle activation during planks, when they were done in slings, a closer look at the full-text of the study reveals that doing your planks in slings is a very useful way to increase the activation of the rectus femoris, the external obliques and the serratus anterior (see Figure 2).
    Figure 2: Root mean square (RMS) muscle activation recorded from (A) rectus abdominis and external oblique (B) rectus femoris and serratus anterior during each 3-second plank. Significant difference in activation between the plank type indicated by a, b, c, d, e ( p < 0.05). Norm—plank on floor; FeetIn—feet suspended; ArmsIn—forearms suspended; Full—forearms and feet suspended. MVC = maximal voluntary contraction (Byrne. 2014).
    As mentioned previously in context of the study by Snarr & Esco, "caution should be taken for those individuals with a previous history or weakness in the lumbar region due to the increases in erector spinae activation during instability planks." (Snarr. 2014 | learn more in the corresponding SuppVersity Facebook news)
  • Alternate interval training for superior results. Scientists from the University of Georgia conducted an experiment to determine the cardiorespiratory, metabolic, and perceptual responses to a low-volume, high-intensity protocol of calisthenic exercise.
    "The purpose of the study was to document and compare the physiological responses to 2 high-intensity intermittent exercise protocols: repeated bouts of sprint interval cycling (SIC) and repeated bouts of high-intensity intermittent calisthenics (HIC)" (Gist. 2014)
    The authors of the corresponding paper hypothesized that HIC would elicit physiological responses similar to SIC and of sufficient cardiovascular strain to classify its peak responses as vigorous... and guess what?

    Table 1: Physiological VO2 & heart rat (HR) response to cycling (SIC) and calisthenics (HIC) training in the study at hand (Gist. 2014)
    The physiological response to the calisthenics vs. cycling trial was more or less identical (see Table 1). A statistical significant difference in the cardiovascular response of the 11 (8 men and 3 women) normal-weightmoderately trained, college-aged participants was observed only at the onset of the exercise, where the VO2peak increased to a significantly greater extend in the cycling vs. calisthenics group, in which the subjects performed as many burpees as possible for 30 seconds followed by 4 minutes of active recovery (stepping in place at self-selected pace).

    Overall, the results of the study at hand do thus suggest that those of you who hate cycling can as well do their burpees to elicit a similar physiological response. And while we would theoretically have to confirm that the long-term outcomes of both training protocols will be identical, as well. I personally believe that the burpee protocol will have significantly more pronounced effects in the body composition and overall conditioning domain. Previous studies have after all suggested that exercises that involve the whole body are generally more effective than exercises like cycling where only one muscle group is working.
  • 14 weeks of regular exercise will improve some health markers, but won't have college students lose weight or fat. That's the relatively unsurprising finding of a recent study from the George Washington University.

    The authors of the corresponding papers measured whether the college “activity” courses that are designed to give participants exposure to, and practice with, safe exercise techniques will also alter physiological characteristics, such as blood pressure or strength. The study involved 79 students from several sections of exercise and conditioning classes at our university. The classes included a variety of fitness- and strength-oriented exercises. Physiological and performance measurements were collected in weeks 2 (pretest) and 14 (posttest), and compared pre with post using paired t-tests subject to Bonferroni correction (significant p < 0.0055).
    Table 2: Pre and post values for the measured parameter | *HR = heart rate; SBP = systolic blood pressure; DBP = diastolic blood pressure; BW = body weight; %BF = percent body fat; HG = hand grip strength; PU = push-ups; SU = sit-ups; HRrec = HR recovery (Danoff. 2014)
    As you can see in Table 2, there were significant improvements in resting heart rate (HR) (73 vs. 70 b·min-1, p < 0.002), hand grip strength (250 vs. 272 N, p < 0.001), push-ups (29 vs 37, p < 0.001), sit-ups (32 vs. 35, p < 0.001), and step test HR recovery (122 vs. 110 b·min-1, p < 0.001).

    What did not change, though were systolic and diastolic blood pressures, body weight, and percent body fat did not change - a typical result for any low(er) intensity exercise only (no dietary component) intervention.
If you are looking to increase your bench, you may want to try training with elastic bands | learn why.
Come back tomorrow! If you liked today's research update, I highly suggest you come back tomorrow for more news from the realms of exercise science, including the effects of interval, strength and combined training on muscle fiber size and myostatin expression, the surprisingly pronounced increase in lower body muscle mass in response to six weeks of vibration training, the differential effects of caffeine on large and small muscle groups and much more... and while you are waiting for part II of this research update to be published, I recommend doing a couple of sets of burpees | Post video evidence on FB ;-)
    References:
    • Byrne et al. "Effect of Using a Suspension Training System on Muscle Activation During the Performance of a Front Plank Exercise." Journal of Strength & Conditioning Research 28.11 (2014): 3049–3055.
    • Danoff & Raupers. "Effect of a One-Semester Conditioning Class on Physiological Characteristics of College Students." Journal of Strength & Conditioning Research 28.11 (2014):3115–3120.
    • Gist, et al.  "Comparison of Responses to Two High-Intensity Intermittent Exercise Protocols." Journal of Strength & Conditioning Research 28.11 (2014): 3033–3040.
    • Snarr & Esco. "Electromyographical Comparison Of Plank Variations Performed With And Without Instability Devices." Journal of Strength & Conditioning Research: Post Acceptance: September 26, 2014 
    • Walker & Hakinnen. "Similar Increases in Strength After Short-Term Resistance Training Due to Different Neuromuscular Adaptations in Young and Older Men." Journal of Strength & Conditioning Research 28.11 (2014): 3041–3048.

    Exercise Research Update: Sprints for Endurance Athletes, Bench vs. Band-Assisted Push Up, HIIT in Hypoxia, Stiff-Legged Deadlifts vs. Leg Curls + 5 Add. Recent Studies

    If you want the latest in strength and conditioning research, today's SuppVersity article is for you!
    I am not sure if you are following belong to the readership of the Journal of Strength & Conditioning Research. As a SuppVersity reader you have yet read your share of analyses and interpretations of data from studies that have been published in this journal.

    Usually, only two to three articles per publication cycle make the SuppVersity Cut and are discussed at length, here at www.suppversity.com. For January 2015, I have decided to go take a different approach. I will present a broader range of articles and selected results to give you a better idea of what's going on this field of research. If you like this approach, let me know... who knows, maybe this is going to be the first in a new series of articles ;-)
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    • Doing deadlifts builds core strength, strength that transfers to other exercises (Thompson. 2015) - I suppose you will have heard that "deadlifts are the #1 all-round strength builder". Now, I guess you will agree that this may be an overgeneralization, if not an exaggeration; and still, the results of the latest study from the Human Performance Laboratory at the Texas Tech University confirm once again: deadlifts ain't for meat heads only.

      In their well-powered study in young soccer players, Thompson et al. examined the effects of 10 weeks of barbell deadlift training on rapid torque characteristics of the knee extensors and flexors and analyzed the relationships between training-induced changes in rapid torque and vertical jump performance.

      Fifty-four subjects (age, mean ± SD = 23 ± 3 years) were randomly assigned to a control (n = 20) or training group (n = 34). Subjects in the training group performed supervised deadlift training twice per week for 10 weeks. All subjects performed isometric strength testing of the knee extensors and flexors and vertical jumps before and after the intervention. Torque-time curves were used to calculate rate of torque development (RTD) values at peak and at 50 and 200 milliseconds from torque onset.
      Figure 1: The deadlifts pay off in terms of strength gains and those gains transfer to other explosive, performance-based tasks - in this case vertical jumps (Thompson. 2015).
      As you can see in Figure 1, the barbell deadlift training induced significant pre- to post-increases of 18.8–49.0% for all rapid torque variables (p < 0.01). Vertical jump height increased from 46.0 ± 11.3 to 49.4 ± 11.3 cm (7.4%; p < 0.01), and these changes were positively correlated with improvements in RTD for the knee flexors (r = 0.30–0.37, p < 0.01–0.03).
    Deadlifting can help w/ back pain, but it ain't for everyone.
    Deadlifting for back pain?! Recently Berglund et al. investigated whether there are certain criteria that identify patients with back pain who will benefit from deadlifting. What they found was that participants with less disability, less pain intensity and higher performance on the Biering-Sorensen test, which tests the endurance of hip and back extensor muscles, at baseline benefit from deadlift training. In that the Biering-Sorensen test, a test for asymptomatic subjects and subjects reporting current or previous nonspecific low back pain, was the strongest predictor. Pain intensity was the next best predictor as it was included in two predictive models.

    Accordingly, the authors conclude that "strength and conditioning professionals who use the deadlift as a rehabilitative exercise for individuals with mechanical low back pain, it is important to ensure that clients have sufficient back extensor strength and endurance and a sufficiently low pain intensity level to benefit from training involving the deadlift exercise" (Berglund. 2015).
    • The scientists point out that their findings prove that "a 10-week barbell deadlift training program [is] effective at enhancing rapid torque capacities in both the knee extensors and flexors" (Thompson. 2015). Furthermore, the changes in rapid torque were associated with improvements in vertical jump height, which suggest that doing deadlifts is not a waste of time if you are no powerlifter. After all, the adaptations from deadlift training obviously transfer to other explosive, performance-based tasks. Accordingly, Thompson et al. conclude: "Professionals may use these findings when attempting to design effective, time-efficient resistance training programs to improve explosive strength capacities in novices" (Thompson. 2014).
    • Having athletes performing in aerobic sports to add. anaerobic training is nothing but beneficials (Stevens. 2015) -  The researchers from the Western University had 16 trained oarsmen perform a 2,000-m time-trial performance to test whether replacing part of their regular aerobic training with spring training would have beneficial or negative effects on their exercise performance.

      What Stevens et al. found was that the EBTSIT protocol which involved 10 sprint interval (SIT) sessions over 4 weeks, in addition to 12 continuous exercise sessions, 2 anaerobic threshold exercise sessions, and 4 strength training sessions lead to significant improvements in time trial performance, while the classic approach did not.
      Figure 2: Changes in time trial performance (left) and peak power (right) after regular (aerobic only) or regular + sprint training in 16 trained oarsmen (Stevens. 2015).
      Furthermore, the power-output in a 60-second “all-out” anaerobic capacity test increased significantly with EBTSIT (PPO: EBTSIT: baseline = 566 ± 82, post = 623 ± 60 W; p = 0.02) but not with EBTAlone (EBTAlone: baseline = 603 ± 81, post = 591 ± 123 W; p = 0.59).

      Accordingly, the scientists conclude that "replacing a portion of EBT with SIT can improve both 2,000-m erg performance and anaerobic capacity, while maintaining aerobic fitness in trained oarsmen" (Stevens. 2015). For trainees and trainers it can thus be recommended to incorporate SIT within endurance training programs during periods of low-volume training, to improve performance without sacrificing aerobic capacity.
    • Burpees have proven to be a conditioning HIIT, already | learn why!
      Burpees beat traditional weight training - as far as the metabolic response is concerned (Ratamess. 2015) -- The purpose of this recent study from the College of New Jersey was to quantify and compare the acute metabolic responses to resistance exercise protocols comprising free-weight, body-weight, and battling rope (BR) exercises.

      Ten resistance-trained men (age = 20.6 ± 1.3 years) performed 13 resistance exercise protocols on separate days in random order consisting of only one exercise per session.

      For free-weight exercise protocols, subjects performed 3 sets of up to 10 repetitions with 75% of their 1 repetition maximum.
      • For the push-up (PU) and push-up on a BOSU ball protocols, subjects performed 3 sets of 20 repetitions.
      • For the burpee and PU with lateral crawl protocols, subjects performed 3 sets of 10 repetitions.
      • For the plank and BR circuit protocols, subjects performed 3 sets of 30-second bouts.
      A standard 2-minute rest interval (RI) was used in between all sets for each exercise. Data were averaged for the entire protocol including work and RIs.

      Table 1: Ventilation (VE) and heart rate (HR) in response to the different exercises (Ratamess. 2015).
      Mean oxygen consumption was significantly greatest during the BR (24.6 ± 2.6 ml·kg−1·min−1) and burpee (22.9 ± 2.1 ml·kg−1·min−1) protocols. For the free-weight exercises, highest mean values were seen in the squat (19.6 ± 1.8 ml·kg−1·min−1), deadlift (18.9 ± 3.0 ml·kg−1·min−1), and lunge (17.3 ± 2.6 ml·kg−1·min−1). No differences were observed between PUs performed on the floor vs. on a BOSU ball. However, adding a lateral crawl to the PU significantly increased mean oxygen consumption (19.5 ± 2.9 ml·kg−1·min−1). The lowest mean value was seen during the plank exercise (7.9 ± 0.7 ml·kg−1·min−1).

      As the authors point out, their "data indicate performance of exercises with BRs and a body-weight burpee exercise elicit relatively higher acute metabolic demands than traditional resistance exercises performed with moderately heavy loading" (Ratamess. 2015).
    • Fat does, muscle doesn't impair an endurance athlete's performance (Maciejczyk. 2015) - Recent evidence suggests that not only body fat (BF) but high lean body mass (HLBM) adversely affects aerobic performance and may reduce aerobic endurance performance as well. However, the influence of body composition on anaerobic performance remains controversial.

      The latest study by scientists from the University of Physical Education in Krakow was thus aimed to examine the effects of increased body mass (BM) and body composition on cycling anaerobic power. Peak power (PP) and mean power (MP) measurements were conducted in 2 groups of men with similar total BM but different body compositions resulting from (a) high level of BF [HBF group] or (b) high level of lean body mass [HLBM group] and in a control group.
      Figure 3: Absolute peak power vs. body fat (left) and lean mass (right) - both correlate (Maciejczyk. 2015).
      As you can see, the absolute PP (shown in Figure 3 and MP (not shown) were significantly higher in the HLBM group compared with the control and HBF groups. However, PP and MP relative to BM and using allometric scaling were similar in the HLBM and control groups, yet significantly higher than in the HBF group. There were no significant differences between groups in PP and MP when presented relative to LBM.

      Therefore, the scientists are right, when they say that "it seems that it is not BM but rather body composition that affects PP," the only problem is: By taking people who were "fat" and "lean" in the first place, it's impossible to tell which came first: Being fat or having a reduced cycling performance.
    Wow, this article is getting longer and longer!Obviously, there are more studies. Studies I am about to review even more briefly to keep you up-to-date without however keeping you up all night reading an article that's longer than 10,000 words ;-)
    • Band assisted push ups. This is how it's supposed to look like if you want them to be as potent as regular bench presses (photo from Calatayud. 2015)
      Bench and band-assisted push up activate the pecs to the same degree and result in similar strength gains (Calatayud. 2015) - That's the unsurprising result of a recent study by Calatayud et al. (2015). A result that must be interpreted with caution, though, because it was observed in previously resistant trained, but not necessarily "bodybuilder-" or "powerlifter-like" trainees.

      Whether the same holds true for elite bodybuilders and powerlifters would have to be seen. Plus: I am not sure if all of you are willing to scrap their beloved bench presses for the band-assisted push-ups shown in the image to the right ;-)
    • Specific performance benefits of HIIT in hypoxia (Brocherie. 2015) - Compared to regular high intensity interval training, the addition of 10 repeated-sprint training sessions performed in hypoxia vs. normoxia to their regular football practice over a 5-week in-season period was more efficient at enhancing repeated-agility (RA) (6 × 20 m, 30-s rest) ability (including direction changes) youth highly trained football players.

      The scarcity of oxygen during the HIIT sessions had yet no additional effect on improvements in lower-limb explosive power, maximal sprinting, and run-based high-intensity repeated-sprint ability (RSA) performance.
    • No need to warm up your inspiratory muscles (Arend. 2015) - Well, the statement may be a tad too general, but at least for the protocol used in a recent study by Arend et al. it appears as if - despite some changes in respiratory parameters -  it "does not have a significant influence on submaximal endurance performance in highly trained male rowers" (Arend. 2015).

      The fact that there were no acute benefits also doesn't negate beneficial effects of chronic inspiratory muscle training. Many of the previous studies on chronic benefits are with some exceptions (Chatham. 1999) mostly similarly disappointing (Inbar. 2000; Williams. 2002), though.
    • Stiff-legged deadlifts and leg curls differentially activate the hamstring muscles (Schoenfeld. 2015) - It's a good question whether you can do only one, or have to do multiple exercises to maximally stimulate a given muscle group.

      In the case of the hamstrings, a recent study by Schoenfeld, et al. suggests that two exercises, more specifically, the stiff-legged deadlift and the hamstring curl, may be better than one.
      Figure 4: EMG activity of the lower lateral and lower medial part of the hamstring during lying leg curls (LLC) and stiff-legged deadlifts (SLD) in 10 experienced resistance trainees (Schoenfeld. 2015)
      In their study which used surface electromyography to record mean normalized muscle activity of the upper lateral hamstrings, lower lateral hamstrings, upper medial hamstrings, and lower medial hamstrings, the lying leg curl (LLC) elicited significantly greater normalized mean activation of the lower lateral and lower medial hamstrings compared with the stiff-legged deadlift (SLDL) (p ≤ 0.05).

      As Schoenfeld et al. point out, "[t]hese findings support the notion that the hamstrings can be regionally targeted through exercise selection." The authors are yet also right, when they say that "[f]urther investigations are required to determine whether differences in activation lead to greater muscular adaptations in the muscle complex" (Schoenfeld. 2015), because in contrast to what most trainees believe, this is often not the case.
    • Caffeine is ergogenic, adding nitrates on top is useless (Glaister. 2015) - In a randomized, counterbalanced, double-blind study, the 14 competitive female cyclists (age: 31 ± 7 years; height: 1.69 ± 0.07 m; body mass: 61.6 ± 6.0 kg) experienced the same performance increases on a 20-km time trials on a racing bicycle regardless of whether the ingested 5mg/kg caffeine alone or in combination with a 70-ml dose of concentrated beetroot juice containing either 0.45 g of dietary nitrate.
    • Hitting the weights elicits the same testosterone response in the AM & PM (Shariat. 2015) - Based on the results Shariat et al. present in their recent paper, there is no difference in the testosterone response between AM and PM resistance training.
      Figure 5: There is no correlation between the post-workout increase in testosterone and lean mass gains (left) or strength gains (right) during a std. 12-week resistance training program, anyway (West. 2012). So, even if the study had yielded different results, they would have been of questionable practical relevance.
      And honestly, even if there was a difference, the latter would probably be irrelevant, because there is as of yet no evidence that the post-workout increase in testosterone correlates with increased long(er) term strength or size gains (West. 2012).

      Since this is not much different for IGF-1, the results of another study from the latest issue of the Journal of Strength and Conditioning Research by Vilaça-Alves et al. (2015) is of similarly questionable practical relevance. In said study, the researchers observed significantly higher post-workout increase in IGF-BP3, an IGF binding protein that increases proportional to IGF-1, when the strength workout was done after the endurance training vs. the other way around.
    • Six weeks "on the vibrator" are good for rusty, old muscle (Perchthaler. 2015) - In spite of the fact that I am 100% convinced that six weeks of "real" resistance training would have produced significantly more beneficial effects, I cannot ignore that the 6-week vibration training intervention led to significant increases in jump height increased by 18.55% (p < 0.001) and corresponding increases in multijoint strength performance of the lower limbs.

      In view of the fact that the exercise was perceived as "very easy" to "somewhat hard", i.e. having a score of only 7-13 of Borg's scale, it would be a good ans easy starter for those grandpas and grandmas who feel that lifting weights or machine training is too hard for them. That the latter would be the better / more effective choice should be obvious, though.
    Push-ups and pull-ups burn 50% and 62% more energy than previously thought, study from January 2014 shows | read the full article
    You made it! And I made it, too. This article got significantly longer than I had intended it to be. I hope it was worth the effort and you still enjoyed it (comments welcome). My personal, highlight by the way is the "Burpee" study by Ratemess. Why? Well, it makes me feel good that the subjects found those body weight exercises similarly exhausting as I did, when I reincorporated them into my workouts about 6 months ago ;-)

    Alright, now enjoy your day and let me know if you want future long(ish) research updates like this one to appear in regular intervals here | Comment on Facebook.
    References:
    • Arend, M, Mäestu, J, Kivastik, J, Rämson, R, and Jürimäe, J. Effect of inspiratory muscle warm-up on submaximal rowing performance. J Strength Cond Res 29(1): 213–218, 2015 
    • Berglund, Lars M.Sc., RPT; Aasa, Björn M.Sc., RPT; Hellqvist, Jonas M.Sc., RPT; Michaelson, Peter Ph.D., RPT; Aasa, Ulrika Ph.D., RPT. "Which patients with low back pain benefit from deadlift training?" Journal of Strength & Conditioning Research: Post Acceptance: December 31, 2014.
    • Brocherie, F, Girard, O, Faiss, R, and Millet, GP. High-intensity intermittent training in hypoxia: A double-blinded, placebo-controlled field study in youth football players. J Strength Cond Res 29(1): 226–237, 2015.
    • Chatham, K., et al. "Inspiratory muscle training improves shuttle run performance in healthy subjects." Physiotherapy 85.12: 676-683, 1999.
    • Calatayud, J, Borreani, S, Colado, JC, Martin, F, Tella, V, and Andersen, LL. Bench press and push-up at comparable levels of muscle activity results in similar strength gains. J Strength Cond Res 29(1): 246–253, 2015 
    • Glaister, M, Pattison, JR, Muniz-Pumares, D, Patterson, SD, and Foley, P. Effects of dietary nitrate, caffeine, and their combination on 20-km cycling time trial performance. J Strength Cond Res 29(1): 165–174, 2015.
    • Inbar, O, et al. "Specific inspiratory muscle training in well-trained endurance athletes." Medicine and science in sports and exercise 32.7: 1233-1237, 2000.
    • Maciejczyk, M, Wiecek, M, Szymura, J, Szygula, Z, and Brown, LE. Influence of increased body mass and body composition on cycling anaerobic power. J Strength Cond Res 29(1): 58–65, 2015.
    • Perchthaler, D, Grau, S, and Hein, T. Evaluation of a 6-week whole-body vibration intervention on neuromuscular performance in older adults. J Strength Cond Res 29(1): 86–95, 2015
    • Ratamess, NA, Rosenberg, JG, Klei, S, Dougherty, BM, Kang, J, Smith, CR, Ross, RE, and Faigenbaum, AD. Comparison of the acute metabolic responses to traditional resistance, body-weight, and battling rope exercises. J Strength Cond Res 29(1): 47–57, 2015.
    • Schoenfeld, BJ, Contreras, B, Tiryaki-Sonmez, G, Wilson, JM, Kolber, MJ, and Peterson, MD. Regional differences in muscle activation during hamstrings exercise. J Strength Cond Res 29(1): 159–164, 2015.
    • Stevens, AWJ, Olver, TT, and Lemon, PWR. Incorporating sprint training with endurance training improves anaerobic capacity and 2,000-m erg performance in trained oarsmen. J Strength Cond Res 29(1): 22–28, 2015.
    • Shariat, A, Kargarfard, M, Danaee, M, and Bahri Mohd Tamrin, S. Intensive resistance exercise and circadian salivary testosterone concentrations among young male recreational lifters. J Strength Cond Res 29(1): 151–158, 2015.
    • Thompson, BJ, Stock, MS, Shields, JE, Luera, MJ, Munayer, IK, Mota, JA, Carrillo, EC, and Olinghouse, KD. Barbell deadlift training increases the rate of torque development and vertical jump performance in novices. J Strength Cond Res 29(1): 1–10, 2015 
    • West, Daniel WD, and Stuart M. Phillips. "Associations of exercise-induced hormone profiles and gains in strength and hypertrophy in a large cohort after weight training." European journal of applied physiology 112(7): 2693-2702, 2012.
    • Vilaça-Alves, J, Fernandes, HM, Saavedra, FJ, Pinto, RS, and dos Reis, VM. Order effects of combined strength and endurance training on testosterone, cortisol, growth hormone, and IGF-1 binding protein 3 in concurrently trained men. J Strength Cond Res 29(1): 74–79, 2015—
    • Williams, James S., et al. "Inspiratory muscle training fails to improve endurance capacity in athletes." Medicine and science in sports and exercise 34.7: 1194-1198, 2002.