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Sabtu, 23 April 2016

BFR, Detraining Mass & Strength | Multiple Sets Multiply 'Ur EE | 1- vs. 2-Arm Kettle Bell Swings Rock the Core & More

The # of hands you use to hold your KB while doing swings determines core muscle activity.
With the publication of the latest issue of the The Journal of Strength & Conditioning Research (May 2016 - Volume 30 - Issue 5 | read it), the time has come to do a training science update with data on the effects on blood flow restriction on strength and size gains during detraining, the energetic demands of single vs. multi-set training, the highly significant core muscle activity patterns with single- vs. two-arm kettlebell swings and a handful of auxilliary studies summarized in the bottom line... Sounds interesting? Well, then I don't want to keep you any longer. Let's see which insights said studies have to offer...
You can use BFR powered detraining in your periodization schemes.

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  • Low intensity blood flow restriction training done during three times per week during 6 weeks of detraining helps maintain mass in in phys. active subjects (Kim. 2016).

    Compared to vigorous cycling at 60–70% of the subjects' individual heart rate reserve [HRR] without BFR, the low-intensity cycling protocol (30% HRR) with BFR (160–180 mm Hg) Kim et al. prescribed to their subjects, thirty-one healthy college-aged males (22.4 ± 3.0 years, range: 19–30 years), actually increased the leg lean mass of the subjects over time.
    Table 1: Strength and body composition data - *LI-BFR = low-intensity cycling with BFR; CON = control; BFLBM = bone-free lean body mass; ES = effect size; VI = vigorousintensity (Kim. 2016)
    The strength development in both groups was identical, though. This and the fact that cycling is not exactly what you should do to maintain strength and size (learn more about detraining) are yet things you have to keep in mind, before freaking out about how "awesome" BFR is.
  • Study unsurprisingly confirms the superior energy requirements of multiple- vs. single-set workouts - Difference is larger than 100%, in young men and women (Mookerjee. 2016).

    In their study, the researchers from the Universities of Pennsylvania and Cumberlands, as well as the College of New Jersey compare energy expenditure (EE) of single-set and multiple-set resistance exercise protocols using indirect calorimetry.
    Table 2: Loads (kg) used for each exercise presented by gender and combined data (Mookerjee. 2016).
    Twelve men and twelve women (age = 21.4 ± 1.3 years) performed a single-set (SS) and multiple-set (MS) resistance exercise protocol in random order. The subjects performed two protocols at 70% of their 1-repetition maximum. The protocols consisted of 5 upper-body exercises of either 1 or 3 sets per exercise performed in random order. Metabolic and cardiorespiratory data were recorded over the entire exercise session and during 5 minutes of recovery by a portable metabolic measurement system.
    Figure 1: Gross and net (left), as well as relative (per lbm) EE in kcal during SS (single set) and MS (multiple set) training in male and female study participants (Mookerjee. 2016).
    As you can see in Figure 1, the gross (167.9 ± 58.7 kcal) and net (88.3 ± 41.6 kcal) EE for the MS protocol were significantly greater (p < 0.001) than gross (71.3 ± 26.5 kcal) and net (36.3 ± 18.7 kcal) EE of the SS protocol. Conversely, there was no significant difference in the rate of EE between both protocols. Heart rate, respiratory rate, relative V[Combining Dot Above]O2, respiratory exchange ratio, and minute ventilation values were significantly higher during the MS than the SS protocol.

    As it was to be expected, a significant gender difference (p < 0.001) in absolute and relative EE was observed for both protocols where values in men were higher than women. 
  • Doing kettle bell swings with one vs. two arms induces a greater neuromuscular activity for the contralateral side of the upper erector spinae and ipsilateral side of the rectus abdominis, and lower activation of the opposite side of the respective muscles (Anderson. 2016).

    The aim of the study of this study from Norway was to compare the electromyographic activity of rectus abdominis, oblique external, and lower and upper erector spinae at both sides of the truncus in 1-armed and 2-armed kettlebell swing. To this ends, the researchers had sixteen healthy men perform 10 repetitions of both exercises using a 16-kg kettlebell in randomized order.
    Figure 2: Comparison of the EMG activity of the core muscles 1- vs. 2-armed kettle bell swings in sixteen healthy men (age, 25 ± 6 years; body mass, 80 ± 8 kg; stature, 180 ± 7 cm) with 7 ± 7 years of resistance training experience (Anderson. 2016)
    As the data in Figure 2 reveals, For the upper erector spinae, the activation of the contralateral side during 1-armed swing was 24% greater than that of the ipsilateral side during 1-armed swing (p < 0.001) and 11% greater during 2-armed swing (p = 0.026). Furthermore, the activation in 2-armed swing was 12–16% greater than for the ipsilateral side in 1-armed swing (p < 0.001). For rectus abdominis, however, 42% lower activation of the contralateral side was observed during 1-armed swing compared with ipsilateral sides during 2-armed swing (p = 0.038) and 48% compared with the ipsilateral side during 1-armed swing (p = 0.044). Comparing the different phases of the swing, most differences in the upper erector spinae were found in the lower parts of the movement, whereas for the rectus abdominis, the differences were found during the hip extension. In contrast, similar muscle activity in the lower erector spinae and external oblique between the different conditions was observed (p = 0.055–0.969). In conclusion, performing the kettlebell swing with 1 arm resulted in greater neuromuscular activity for the contralateral side of the upper erector spinae and ipsilateral side of the rectus abdominis, and lower activation of the opposite side of the respective muscles.
Normalized electromyography (EMG) amplitude values (mean 6 SD) for the straight and hexagonal barbells, collapsed across 65 and 85% 1 repetition maximum loads (Camara. 2016) |  ++ significant advantage of regular bar; + significant advantage of hexagnoal bar.
What else have we got? Well, there are Trexel's previously discussed popular creatine vs. caffeine study discussed in July 2015 (read more) and Ohya's 400- and 800-m track running study showing that even trained females' performance suffers from inspiratory muscle fatigue after short-duration running exercise, suggesting that "[c]oaches could consider prescribing inspiratory muscle training or warm-up in an effort to reduce the inevitable IMF associated with maximal effort running" (Ohya. 2016).

Furthermore, Camara's previously (only in the Facebook news) discussed study showing differences in the muscle activity pattens (data see Figure on the right) and significantly greater peak force, peak power, and peak velocity for deadlifts with hexoganal vs. regular bars, and, last but not least has now been officially published.

Last, but not least, Beyer's study showing that 4 weeks of unilateral strength training results in "an increase in strength and size of the trained musculature, and cross education of strength in the untrained musculature, which may occur without detectable changes in muscle size, activation, or the acute hormonal response" (Beyer. 2016) as well as two studies I will discuss in detail, next week, should not be forgotten either | Comment on Facebook!.
References:
  • Andersen, V, Fimland, MS, Gunnarskog, A, Jungård, G-A, Slåttland, R-A, Vraalsen, ØF, and Saeterbakken, AH. Core muscle activation in one-armed and two-armed kettlebell swing. J Strength Cond Res 30(5): 1196–1204, 2016
  • Camara, KD, Coburn, JW, Dunnick, DD, Brown, LE, Galpin, AJ, and Costa, PB. An examination of muscle activation and power characteristics while performing the deadlift exercise with straight and hexagonal barbells. J Strength Cond Res 30(5): 1183–1188, 2016
  • Kim, D, Singh, H, Loenneke, JP, Thiebaud, RS, Fahs, CA, Rossow, LM, Young, K, Seo, D-i, Bemben, DA, and Bemben, MG. Comparative effects of vigorous-intensity and low-intensity blood flow restricted cycle training and detraining on muscle mass, strength, and aerobic capacity. J Strength Cond Res 30(5): 1453–1461, 2016
  • Mookerjee, S, Welikonich, MJ, and Ratamess, NA. Comparison of energy expenditure during single-set vs. multiple-set resistance exercise. J Strength Cond Res 30(5): 1447–1452, 2016
  • Ohya, T, Yamanaka, R, Hagiwara, M, Oriishi, M, and Suzuki, Y. The 400- and 800-m track running induces inspiratory muscle fatigue in trained female middle-distance runners. J Strength Cond Res 30(5): 1433–1437, 2016.
  • Trexler, ET, Smith-Ryan, AE, Roelofs, EJ, Hirsch, KR, Persky, AM, and Mock, MG. Effects of coffee and caffeine anhydrous intake during creatine loading. J Strength Cond Res 30(5): 1438–1446, 2016

Rabu, 17 Februari 2016

Research Update: 5000 IU/day Vitamin D, 12g/day Citrulline Malate or Barefoot Running What's the Most Ergogenic?

Who would have thought that barefoot running triggers instant improvements in running economy?
With the release of ahead of print articles for the next issue of the Journal of Strength and Conditioning Research, it is high time for yet another research update; an update with research on the effect of vitamin d supplementation on training adaptation in well trained soccer players, acute citrullin malate supplementation (10 grams 60 minutes before a workout) and high-intensity cycling performance, as well as information about the ability of barefoot running to reduce oxygen cost and improve running economy in female distance runners who have never run barefoot before.
Read more about exercise-related studies at the SuppVersity

Tri- or Multi-Set Training for Body Recomp.?

Aug '15 Ex.Res. Upd.: Nitrate, Glycogen, and ...

Pre-Exhaustion Exhausts Your Growth Potential

Full ROM ➯ Full Gains - Form Counts!

BFR-Preconditio- ning Useless for Weights?

Study Indicates Cut the Volume Make the Gains!
  • The effect of vitamin d supplementation on training adaptation in well trained soccer players (Jastrzebska. 2016) - In view of the fact everybody appears to believe that the currently available evidence would imply that vitamin D supplements could enhance athletic performance, it is hardly surprising that the next issue of the Journal of Strength and Conditioning Research will contain yet another study investigating the effects of vitamin D supplements on athletic performance.

    What distinguishes the study at hand from the rest of the pack is that it was conducted in high-level, well trained athletes, who received either a placebo (PG) or 5000IU of vitamin D per day (SG). Both groups were subjected to the same "High Intensity Interval Training Program".
    Figure 1: Overview of he training regimen, the subjects were subjected to.
    The selection to the groups was based on peak power results attained before the experiment and position on the field. Blood samples for vitamin D level were taken from the players. In addition, total work, 5-10-20-30 m running speed, squat jump, and countermovement jump height were determined.

    Much to the disappointment of the average vitamin D enthusiast, there were no significant differences between SG and PG groups for any power-related characteristics at baseline. What did work, though, was the training: All power-related variables, except the 30 m sprint running time, improved significantly in response to interval training. However, the mean change scores (the differences between post- and pre-supplementation values) did not differ significantly between SG and PG groups. Thus, the authors of the study conclude that...
    Remember the differential effect of Vitamin D on breast cancer risk in lean vs. obese women?
    "[...] an 8-week vitamin D supplementation in highly trained football players was not beneficial in terms of response to high intensity interval training [and that, g]iven the current level of evidence, the recommendation to use vitamin D supplements in all athletes to improve performance or training gains would be premature" (Jastrzebska. 2016).
    What may make sense, however, is to avoid a seasonal decrease in 25(OH)D level or to obtain optimal vitamin D levels via higher dietary intakes and, optionally, vitamin D supplementation. Why that? Well, in vitamin D deficient athletes, there's at least some evidence that supplementing, or rather increasing the 25OHD levels help.
  • Acute Citrulline-Malate supplementation and high-intensity cycling performance (Cunniffe. 2016) - Unlike the results of a previously discussed study on the effects of citrulline supplementation during an intense leg workout, in which 8g/day triggered significant performance increases, the recent double-blind, placebo-controlled, crossover study by Cunniffe et al. found no benefits of 12g of citrulline malate (in 400ml) compared to lemon sugar-free cordial (Placebo [PL]) when the 10 subjects consumed it 60 min prior to completion of two exercise trials... or, to be precise, only the heart rate differed significantly.
    Figure 2: Mean performance in the two groups; # sign. inter-group difference (p < 0.05 | Cunniffe. 2016)
    They consumed it 60 minutes before the workouts? Right, this happens to be the same protocol, Wax et al. used 2014 in 12 advanced resistance trained male subjects. What was different, however, is the type of exercise. While Wax et al. had their subjects squat and leg press, Cunniffe investigated the effects in a trial that consisted of ten (x 15 s) maximal cycle sprints (with 30 s rest intervals) followed by 5 min recovery before completing a cycle time-to-exhaustion test (TTE) at 100% of individual peak power (PP). I guess that explains the difference and suggest that the performance enhancing effects of citrulline are exercise dependent - obviously, this has to be investigated in future studies ;-)
  • Barefoot running reduces the submaximal oxygen cost in female distance runners (Berrones. 2016) - The two most important ways to increase your running performance are (a) improving your VO2max, (b) improving your running economy aka the "O2 costs of running". That this can be achieved as easily as by dropping your shoes is thus a quite important result, Berrones et al. observed in during three 5-minute submaximal running trials representing 65, 75, and 85% of VO2max in fourteen recreationally active, trained distance female runners (age = 27.6 +/- 1.6 yrs; height = 163.3 +/- 1.7 cm; weight = 57.8 +/- 1.9 kg) who were completely inexperienced with unshod running.

    Following initial testing, each subject was randomized to either unshod or shod for days 2 and 3. Berrones et al. analyzed the data with a 2-way (condition by intensity) repeated measures ANOVA. The results of this analysis shows that the runners' submaximal oxygen consumption was significantly reduced at 85% of VO2max (P = 0.018), but not during the 65% or 75% trials (P > 0.05, both).
    The improvement in VO2 consumption during barefoot running was sign. only for 85% VO2max (Berrones. 2016).
    No other dependent measure, i.e. respiratory exchange ratio (RER), lactate, heart rate (HR), and ratings of perceived exertion (RPE), was different between unshod and shod conditions; and still, the scientists' conclusion that "training or competing while barefoot may be a useful strategy to improve endurance performance" (Berrones. 2016) may be useful for recreational or competitive distance runners.
You want more short exercise news? Well, this is not exactly a short one, but still: "GYM-Science Update: Bands Aid W/ Deadlifts? 16x1 or 4x4 for HIIT? Kettlebell HIIT Workout Better Than HIIT-Cycling?" | more
Bottom line? Well, I guess I should answer the question in the headline even if it is obvious, right? The answer is: "barefoot running". What we should not forget, though is the fact that previous research suggests that having normal (not extra-high) vitamin D levels is as important for athletes as 8g of citrulline are useful for strength trainees.

Against that background I wouldn't be surprised if the next SuppVersity Research Update featured studies showing beneficial effects of vitamin D and citrulline malate supplements and no or even ill effects of barefoot running... but hey, the results of the Berrones study are still impressive, right? Don't forget: the subjects had never run barefoot before | Comment on Facebook!
References:
  • Berrones, Adam J.; Kurti, Stephanie; Kilsdonk, Korey; Cortez, Delonyx; Melo, Flavia; Whitehurst, Michael. "Barefoot running reduces the submaximal oxygen cost in female distance runners." Journal of Strength & Conditioning Research: Post Acceptance: January 19, 2016. doi: 10.1519/JSC.0000000000001330. 
  • Cunniffe, Brian; Papageorgiou, Maria; O’Brien, Barbara; Davies, Nathan A; Grimble, George K; Cardinale, Marco. "Acute Citrulline-Malate supplementation and high-intensity cycling performance." Journal of Strength & Conditioning Research: Post Acceptance: January 19, 2016. doi: 10.1519/JSC.0000000000001338.
  • Jastrzebska, Maria; Kaczmarczyk, Mariusz; Jastrzebski, Zbigniew. "The effect of vitamin d supplementation on training adaptation in well trained soccer players." Journal of Strength & Conditioning Research: Post Acceptance: January 20, 2016. doi: 10.1519/JSC.0000000000001337
  • Wax, Benjamin, et al. "Effects of Supplemental Citrulline Malate Ingestion During Repeated Bouts of Lower-body Exercise in Advanced Weight Lifters." The Journal of Strength & Conditioning Research (2014).

Sabtu, 30 Januari 2016

Sleep Science Update: New Insights into the Effect of a Lack of Quality Sleep on Glucose Control and Diabesity Risk

Blue light is not the only enemy of sleep, but it's the most prevalent one, today.
Personally, I believe that sleep, "a condition of body and mind which typically recurs for several hours every night, in which the nervous system is inactive, the eyes closed, the postural muscles relaxed, and consciousness practically suspended" (that's what Google's "define"-feature will tell you about sleep), is still an under-appreciated determinant of optimal health and performance.

Evidence to support this assertion comes from a series of studies that were presented at the Winter Meeting of the British Nutrition Society on December 8-9, 2015 - a meeting with the telling title: "Roles of sleep and circadian rhythms in the origin and nutritional management of obesity and metabolic disease" (O'Sullivan. 2015).
Learn more about the health effects of correct / messed up circadian rhythms

Sunlight, Bluelight, Backlight and Your Clock

Sunlight a La Carte: "Hack" Your Rhythm
Breaking the Fast to Synchronize the Clock

Fasting (Re-)Sets the Peripheral Clock

Vitamin A & Caffeine Set the Clock

Pre-Workout Supps Could Ruin Your Sleep
  • Circadian disruption in shift workers – the effects of insufficient sleep on dietary and lifestyle behaviours (Nea. 2016) - It will not surprise you that shift workers report more sleep problems compared to the general public. Studies estimate that 10–30 % of shift workers suffer from a circadian rhythm disorder known as “shift work disorder”(Gumenyuk. 2012). With their new quantitative study, a team of young researchers from the Dublin Institute of Technology and the University of Ulster provides some insights into the consequences of this problem.

    As the scientists point out, overall, just 34·3 % of the sample was achieving adequate sleep. A number of factors were associated with insufficient sleep – being male (p < 0·001), being 35–54 years of age (p < 0·001), having adult/child dependents (p < 0·001), working in larger organisations (p = 0·045), working in distribution/logistics, manufacturing or construction (p = 0·005), working night shifts (p = 0·042), and working longer shifts (p = 0·002).
    Factors that increased the subject's risk of not getting adequate sleep (Nea. 2016).
    Furthermore, the scientists observed that insufficient sleep had an effect on the diet of workers. Those who did not achieve adequate sleep were more likely to skip meals on working days and skipped meals significantly more frequently (p = 0·023).
    "Workers with insufficient sleep were also significantly less likely to consume the recommended 5 portions of fruit and vegetables per day (37·5 % vs 43·3 %, p = 0·045) and were less likely to consume the recommended 3 portions of milk/cheese/yoghurt per day (11·6 % vs 8·1 %, p = 0·050). In addition, those with insufficient sleep had higher prevalence of hypertension (10·2 % vs 5·7 %, p = 0·008) and depression/anxiety (7·3 % vs 3·4 %, p = 0·008)" (Nea. 2016)
    Participants were also questioned how they perceived shift work impacts on various aspects of their lives. Compared to those who achieve adequate sleep, those who had insufficient sleep were significantly more likely to report that shift work had a negative effect on their physical health (p < 0·001), mental health (p = 0·003), family life (p = 0·001), social life (p = 0·046), physical activity levels (p = 0·029) and overall quality of life (p = 0·002). Those with insufficient sleep were also significantly more likely to report that shift work increases how much alcohol they drink (p = 0·041).
  • Oral glucose tolerance test results are affected by prior sleep duration: a randomised control crossover trial of normoglycaemic adults (Ellison. 2016) - As Ellison et al. rightly point out, "[o]ral glucose tolerance tests (OGTTs) remain the key clinical tool for assessing glucose control and diagnosing diabetes" (Ellison. 2016). In that, they criticize that "[c]urrent guidelines for administering such tests emphasise the importance of a preceding 8 hour fast (often undertaken overnight) but overlook the potential role that preceding sleeping patterns night might play in glucose control the following day" (ibid.). In view of the number of recent observational and experimental studies, which suggest that poor sleep is associated with an increased risk of diabetes, these tests may very well be messed up by a lack of sleep during the previous 8h fast. The aim of the latest study by scientists from the Sound Asleep Laboratory in Leeds was therefore "to explore the effect of early vs. late bedtimes on OGTT results using a cross-over randomised controlled trial" (ibid.).

    To this ends, the authors recruited 40 normoglycemic adults who were, after they had been stratification by self-reported pre-existing sleep patterns (as assessed using the Pittsburgh Sleep Quality Index; PSQI), allocated to either a ‘short’ (2·00am-7·00am) then ‘long’ (10·00pm−7·00am), or a ‘long’ then ‘short’ sleep duration, on two consecutive nights.
    "On each occasion, objective measures of sleep were obtained using the ‘SleepMeister’ application on an iPhone 4, with additional subjective assessments of sleep provided by subsequent completion of a version of the PSQI adapted to generate self-reports of sleep during the preceding night (as opposed to the preceding month). On each of the mornings following ‘short’ or ‘long’ sleep, participants again completed the PSQI and underwent a two-hour 75 g oral glucose tolerance test (OGTT), with blood glucose readings taken at 0, +30, +60, +90 and +120 minutes thereafter using finger-prick tests. Data were analysed using STATA v12. Ethical approval was granted by the University of Leeds REC (Ref:HSLTLM12075)" (Ellison. 2016).
    As it was to be expected, both the ‘SleepMeister’ application and the PSQI recorded significantly later bedtimes (SleepMeister: −19·9; 95 %CI: −20·1,−19·7; PSQI: −19·9; 95 %CI: −20·1,−19·7) and significantly shorter sleep durations (decimal hours: ‘SleepMeister’: −3·8;95 %CI: −4·3,−3·4; PSQI: −3·4; 95 %CI: −3·9,−2·9) following a 2am (vs.10pm) bedtime (i.e. ‘short’ and ‘long’ sleep duration, respectively) - a fact, the scientists consider evidence "that levels of compliance were high" (ibid.).

    In spite of that, there was no significant effect of sleep duration on fasting blood glucose levels prior to the OGTT after adjustment for sleep duration sequence (i.e. ‘short’ then ‘long’ vs. ‘long’ then ‘short’) and a modest imbalance in gender between the two intervention sequence group.
    Figure 2: Normal response (=expected response in OGGT, not the actual response of the subjects, because the absolute values are not disclosed in the abstract and an FT is not yet available) vs. calculated response as a consquence of insufficient sleep (normal + difference, rel. difference above bars | Ellison. 2016).
    What did differ, though, were the glucose levels recorded after the ingestion of 75 g glucose, which were consistently higher following a ‘short’ as opposed to a ‘long’ sleep duration, as well as the levels recorded at +60 and +90 minutes, which were likewise significantly higher by 1·18 mmol/l (95 %CI: 0·43,1·92; p = 0·003) and 0·55 mmol/l (95 %CI: 0·05,1·06; p = 0·032), respectively. These results, the scientists say, "indicate that short sleep duration the night before results in an immediate elevation in blood glucose levels the following morning in normoglycaemic adults" (ibid.). That this is a problem, should be obvious, after all it may falsely classify healthy individuals as pre-diabetics. Therefore, "further standardisation of pre-OGTT sleep duration, similar to that for an overnight fast," (ibid.) appears warranted.
  • Less Sleep Duration and Poor Sleep Quality Lead to Obesity (Parvaneh. 2016) - In a recent cross-sectional study that was carried out to investigate the association of sleep deprivation and sleep quality with obesity, Malaysian scientists analyzed data from 225 Iranian adults (109 males and 116 females) aged 20–55 years.
    "Heart Questionnaire (SHHQ), International Physical Activity Questionnaire (IPAQ) and a 24-hour dietary recall were interview-administered to evaluate sleep pattern, physical activity and dietary intake of the subjects. Besides, anthropometric also were measured, then subjects were categorized into normal weight and over-weight/obese based on WHO (2000). Sleep duration and sleep quality were assessed based on 2 groups of normal weight and overweight/obese" (Parvaneh. 2016).
    The scientists' analysis of the data revealed that overweight/obese individuals have significantly shorter sleep duration (5·37 ± 1·1 hours) as compared to normal weight subjects (6·54 ± 1·06 hours).
    Figure 3: Overweight / obesity is linked to sign. sleep problems (Parvaneh. 2016).
    Sleep duration was yet not the parameter the scientists from the National University of Malaysia identified as a major risk factor for obesity - that was a poor sleep quality, which was associated with a 100% increased risk for being overweight or obese (OR: 2·0, 95 % CI: 1·18–3·37, p < 0·05). As a conclusion, the scientists state that "lower sleep quality and sleep duration increase the risk of being overweight and obese" and demand: "[S]trategies for the management of obesity should incorporate consideration on sleeping pattern" (Parvaneh. 2016). These strategies, by the way, may also help people keep their triglyceride levels in check. After all, another study that was presented at the same meeting of the Nutrition Society suggests that a high sleep efficiency shows a strong and negative correlation with triglycrides and another important marker of heart disease risk, the total cholesterol to HDL ratio (Al Khatib. 2016).
  • Is insulin resistance associated with light at night in healthy sleep deprived individuals? (AlBreiki. 2016) - The simple answer to this question is "Yes!". The more complex one is that a recent study that was designed to investigate the impact of light and/or endogenous melatonin on plasma hormones and metabolites prior to and after a set meal in healthy sleep deprived subjects found that bright blunts the release of melatonin and the effects of insulin on glucose disposal.

    In the study, seventeen healthy participants, 8 females (22·2 years (SD 2·59) BMI 23·62 kg/m2 (SD 2·3)) 9 males (22·8 years (SD 3·5) BMI 23·8 kg/m2 (SD 2·06)) were randomised to a two way cross over design protocol; dim light condition (<5lux) and bright light condition (>500lux), separated by at least seven days.
    Melatonin promotes female weight loss - Suggested Read: "Trying to Lose Fat & Get "Toned"? Taking 1-3 mg Melatonin Helps Women Lose 7% Body Fat, Gain 3.5% Lean Mass".
    "Each session started at 18:00 h and finished at 06:00 h the next day. All participants were sleep deprived and semi-recumbent throughout the session. An isocalorific breakfast was consumed at 08:00 h and lunch was timed to be 10 hours before the evening meal. Each participant consumed an evening meal (1066 Kcal, 38 g protein, 104 g CHO, 54 g fat, 7 g fibre) at an individualised time based on estimated melatonin onset. Plasma and saliva samples were collected at specific time intervals to assess glucose, insulin and melatonin levels" (AlBreiki. 2016).
    As previously stated, the bright light reduced the salivary levels of melatonin significantly (p = 0·005). What is more relevant to the research question, however is that it also increased the postprandial glucose and insulin levels significantly compared to dim lights (p = 0·02, p = 0·001) respectively.

    Figure 3: Effect of light intensity on melatonin levels and glucose response of 8 female and 9 male normal-weight normoglycemic subjects to standardized meal consumed at night (AlBreiki. 2016).
    For the scientists this result is not exactly surprising. They had expected that the melatonin release would be suppressed due to the light intensity; that the increase in insulin was not able to compensate for the light-induced increased glucose resistance, however, shows that the ill effects of a  'night-shift-esque' bright light exposure at night on glucose metabolism are more severe than previously thought.
Redeem your sleep dept, now!
Bottom line: Along with studies highlighting the importance of sufficient hours of quality sleep on glucose control in pregnancy (Alghamdi. 2016; Alnaja. 2016) and the "largest study to-date to demonstrate a strong inverse association between late-onset diabetes and poor sleep, even after adjustment for potential confounding factors" (Alfazaw. 2016), the previously discussed studies highlight that sleep hygiene' is as important for your health as "clean eating" (whatever that maybe) and a sufficient amount of light and intense physical activity | Comment on Facebook!
References:
  • AlBreiki, et al. "Is insulin resistance associated with light at night in healthy sleep deprived individuals?" Proceedings of the Nutrition Society, 75 (2016). 
  • Alfazaw, et al. "Variation in sleep is associated with diagnosis of late-onset diabetes: a cross-sectional analysis of self-reported data from the first wave of ‘Understanding Society’ (the UK Household Longitudinal Study)." Proceedings of the Nutrition Society, 75 (2016). 
  • Alghamdi, et al. "Short sleep duration is associated with an increased risk of gestational diabetes: Systematic review and meta-analysis." Proceedings of the Nutrition Society, 75 (2016). 
  • Alnaja, et al. "Relationship between sleep quality, sleep duration and glucose control in pregnant women with gestational diabetes." Proceedings of the Nutrition Society, 75 (2016). 
  • Al Khatib, et al. "The Sleep-E Study: An on-going cross-sectional study investigating associations of sleep quality and cardio-metabolic risk factors." Proceedings of the Nutrition Society, 75 (2016). 
  • DeFronzo, Ralph A. "The triumvirate: β-cell, muscle, liver. A collusion responsible for NIDDM." Diabetes 37.6 (1988): 667-687.
  • Ellison, et al. "Oral glucose tolerance test results are affected by prior sleep duration: a randomised control crossover trial of normoglycaemic adults." Proceedings of the Nutrition Society, 75 (2016). 
  • Gumenyuk, Valentina, Thomas Roth, and Christopher L. Drake. "Circadian phase, sleepiness, and light exposure assessment in night workers with and without shift work disorder." Chronobiology international 29.7 (2012): 928-936.
  • Nea et al. "Circadian disruption in shift workers – the effects of insufficient sleep on dietary and lifestyle behaviours." Proceedings of the Nutrition Society, 75 (2016). 
  • O’Sullivan (ed.). "Roles of sleep and circadian rhythms in the origin and nutritional management of obesity and metabolic disease." Proceedings of the Nutrition Society. Volume 75 / Issue OCE1 - Winter Meeting, 8–9 December 2015. Published January 2016: E1-E42.
  • Parvaneh, et al. "Less Sleep Duration and Poor Sleep Quality Lead to Obesity." Proceedings of the Nutrition Society, 75 (2016). 
  • Peschke, Elmar. "Melatonin, endocrine pancreas and diabetes." Journal of pineal research 44.1 (2008): 26-40.

Rabu, 25 November 2015

GYM-Science Update: Bands Aid W/ Deadlifts? 16x1 or 4x4 for HIIT? Kettlebell HIIT Workout Better Than HIIT-Cycling?

Deadlifts w/ bands as they were done in the Galpin study (original photo from Galpin's 2015 study | see below).
Time for a news-quickie with the latest science to use at the gym - either for your workouts or just to impress the bros with your knowledge. I mean, who else reads and understands all the latest papers in the #1 strength and conditional journal on earth? Well, you do... ok, you read my laymen summaries, but your bros don't have to know that, do they?

Ok, that's enough of the pseudo-comedian warm-up, let's deadlift the first scientific paper... oh,yeah: Actually the paper is about deadlifting, deadlifting with resistance bands as it is shown in the photo on the right, where a subject performs the deadlift on a force plate.
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  • Deadlift with bands for power and speed - Galpin et al. (2015) investigated how using bands while deadlifting at different loads, namely 60 and 85% of one's individual 1RM, i.e. the maximal weight you can lift for exactly one perfect rep, would influence the power and velocity at which twelve trained men (age: 24.08 ± 2.35 years, height: 175.94 ± 5.38 cm, mass: 85.58 ± 12.49 kg) with deadlift 1 repetition maxima (1RM) of 188.64 ± 16.13 kg pulled the weight off the floor.

    The results of the study show that there were significant peak (yet not relative) power changes irrespective of whether only 15% of the total resistance (group B1) or 35% of the total resistance (group B1) came from the bands (vs. the actual weight).
    Figure 1: Relative changes in power and bar velocity (compared to training w/out bands = control); * denotes sign. difference to control, ** denotes significant difference to control and light bands (Galpin. 2015)
    The effect became even more pronounced and extended from peak to average power, when the subjects used the heavier (85% 1RM) weights. In this condition using bands lead to greater peak and relative power production and lowered the velocity significantly compared to the control condition in which the subjects lifted at the same total level of resistance, albeit without bands (all values in Figure 1 are relative differences).

    For trainees the data in Figure 1 could be highly relevant, because it indicates that heavy bands should be used, when "prescribing the deadlift for speed or power, but not maximal force" (Galpin. 2015). If that's not you, i.e. you're not training for speed and power, but e.g. for size, future long(er)-term studies will have to show whether using bands makes a difference with respect to this study training goal.
  • Interval length, can you really pick whichever suits your best? Even though a recent study by Wesley Tucker et al. (2015) shows that the rate of perceived exertion, as well as the mean heart rate of 14 recreationally active and thus not exactly jacked males who participated in their latest study were identical on 4x4 and 16x1 high intensity interval protocols (i.e. 4 intervals à 4 minutes vs. 16 intervals a 1 minute | see Figure 2), seasoned SuppVersity readers will probably remember that previous studies showed highly relevant differences in the long(er) term effects which obviously cannot be measured in an acute phase study like the one at hand.
    Figure 2: Illustration of the two HIIT protocols, incl. warm-up and cool down on cycle ergometers. White boxes are intervals during which the subjects were supposed to exercise at 90% of their peak heart rate (during the 16x1 protocol this was not achieved by all study participants in the latter intervals, though | Tucker. 2015).
    To be more specific, previous studies on high intensity interval training suggested that athletes who want to increase their VO2 max benefit more from fewer longer intervals, while "Mr. and Mrs. Average" could be better off improving their body composition and metabolic rate with a higher number of short intervals (even as short as 15 seconds in the Tabata protocol). Against that background and in order to explain or contradict the previous findings, it may be worth to consider other study outcomes in Tucker et al. (2015). Study outcomes which did differ. The total energy expenditure, for example, was 19% higher during the 16x1 protocol (p < 0.001) which is in line with the previously referenced recommendation of short intervals for people who are trying to lose weight.
    Figure 3: VO2, heart rate, and energy expenditure during the two HIIT protocols (watch the units! I converted them to be able to put all data into the same graph | Tucker. 2015).
    The VO2 uptake, as well as the maximal heart rates, which could be of interest for endurance athletes, on the other hand, were higher in the 4x4 protocol - a finding that would likewise support the previously voiced recommendation that (endurance) athletes should torture themselves with long(er) intervals to trigger further adaptations in VO2max and heart rate at a given power output.

    Overall, the study at hand will thus not revolutionize your training, but if you haven't read the previous SuppVersity articles, you may still have gotten some new insights into how you may want to adapt your HIIT training in the future.
  • Kettlebell or cycle ergometer? Which do you chose for your HIIT sessions? I've written about kettlebell swings as muscle builders before and I've also hinted at the possibility of using the "bells" for your HIIT workouts. Now, a recent study by Williams and Kraemer shows that
    "[kettlebell high intensity interval training aka] KB-HIIT may [even] be more attractive and sustainable than [sprint interval cycling aka] SIC and can be effective in stimulating cardiorespiratory and metabolic responses that could improve health and aerobic performance" (Williams. 2015).
    The purpose of the study was - you probably already guessed it - to determine the effectiveness of a novel exercise protocol we developed for kettlebell high-intensity interval training (KB-HIIT) in comparison to the classic, standard sprint interval cycling (SIC) exercise protocol most people associate with equipment-based HIIT sessions. To this ends, the researchers from the Southeastern Louisiana University had eight "very active" young men (mean age 21.5 years; body fat 18.52 +/-3.04%, fat free mass 67.44 kg of a total weight of 82.95 kg) complete two 12-minute sessions of KB-HIIT and SIC in a counterbalanced fashion.
    Figure 4: Overview of the KB-HIIT workout (my illustration).
    "In the KB-HITT session [exercises see Figure 4, mean weight depending on exercise and subject 10-22 kg], 3 circuits of 4 exercises were performed using a Tabata regimen.

    In the SIC session, three 30-second sprints were performed, with 4 minutes of recovery in between the first 2 sprints and 2.5 minutes of recovery after the last sprint" (Williams. 2015)
    The study's within-subjects' design over multiple time points allowed Williams and Kraemer to compare the oxygen consumption, the respiratory exchange ratio (RER, a marker of the ratio of fat to carbohydrates that is used as fuel during the workout), the tidal volume (TV, the volume of air that is inspired or expired in a single breath during regular breathing), the breathing frequency (f), the subject's minute ventilation (VE), caloric expenditure rate (kcal/min), and their heart rate (HR) on an individual basis between the exercise protocols. In conjunction with the total caloric expenditure which was likewise measured / calculated and compared. The total amount of data the authors collected was thus quite large.
    Figure 5: Mean total energy expenditure in kcal during the KB and SIC sessions (Williams. 2015)
    Significant inter-group differences were found for VO2, RER, TV and total energy expenditure, with VO2 and total energy expenditure being higher and TV and RER being lower in the KB-HIIT compared with the cycle ergometer HIIT protocol. For f, VE, the energy expenditure per minute and the heart rate, there were no general inter-group differences, but "only" significant group × time interactions. Practically speaking, this means that they changed differently over the course of the whole protocol and are thus maybe relevant for certain athletes, yet not for the general public.

    Overall, the William's and Kraemer's study does therefore support the notion that doing kettlebell HIIT workouts is probably at least on par with the classic cycling HIIT sessions. In view of the increased total caloric expenditure and the lower RER, which signifies a significantly higher fat oxidation during the workout, it is even possible that KB-HIIT would be the better choice for dieters than doing HIIT on a cycle ergometer. Since there is no direct link between fat oxidation and/or energy expenditure during workouts and fat loss, however, long(er)-term studies are necessary to find out whether doing KB-HIIT is in fact more than a equivalent and for many of you maybe funnier alternative to doing HIIT on a cycle ergometer. 
Block Periodization - Training revolution or simple trick? This is what we have to ask ourselves in view of the results of a previously discussed study from 2014 | Read the full SV-Classic article here!
Bottom line: That's it for today; so I suggest you take what you learned, pack it in your gymbag and go and impress your bros at the gym ;-) I am just kiddin'... actually I hope that you can really use some of the information in today's installment of the SuppVersity Short News to make your workouts more productive, more enjoyable and/or simply more versatile.

Personally, I will probably give the KB-HIIT workout a try,... and that even though I expect it to be much harder than cycling which is something I am already used to. But hey, isn't that what training is all about? You have to challenge your body - even if that means conquering your weaker self.

I mean, we all know that as soon as you are staying within the cozy comfort zone of doing the same exercises with the same weights workout after workout your progress will stall; and unless you are one of those people who hit the gym to be able to talk to their athletic friends, that's certainly nothing you should aim for | Comment on Facebook!
References:
  • Galpin, AJ, Malyszek, KK, Davis, KA, Record, SM, Brown, LE, Coburn, JW, Harmon, RA, Steele, JM, and Manolovitz, AD. Acute effects of elastic bands on kinetic characteristics during the deadlift at moderate and heavy loads. J Strength Cond Res 29(12): 3271–3278, 2015
  • Tucker, WJ, Sawyer, BJ, Jarrett, CL, Bhammar, DM, and Gaesser, GA. Physiological responses to high-intensity interval exercise differing in interval duration. J Strength Cond Res 29(12): 3326–3335, 2015
  • Williams, BM and Kraemer, RR. Comparison of cardiorespiratory and metabolic responses in kettlebell high-intensity interval training versus sprint interval cycling. J Strength Cond Res 29(12): 3317–3325, 2015