Wednesday, July 27, 2016

Weights and Barefoot Running are More, EPO Much Less Effective than You May Think. Plus: Stretching & Lactate Monitors and Half-A-Dozen other New Training Studies

Join hands w/ science!
The piles of research that is published on a daily basis is enormous. Not all of it can make it to the SuppVersity News, but studies that made it into the Journal of Strength and Conditioning Research are unquestionably among those that are more likely to make the SuppVersity Cut. Why's that? Well, thematically, they are (pre-)filtered and focusing on the surprisingly beneficial effects of things as different as resistance training and barefoot running, they provide evidence that could be relevant to your own and your clients training.

They will also remind you of the potential benefits and downsides of stretching - and how this is determined by when and how you do it; put the "benefits" of doping with (falsely?) legendary EPO into perspective; and tell you whether the first portable lactate monitor for consumers actually works.
Read more about exercise-related studies at the SuppVersity

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Study Indicates Cut the Volume Make the Gains!
  • Running economy improves in endurance athletes doing medium-volume and -intensity resistance training (Balsalobre-Fernández. 2016) - That's not news, I know, but the fact that a recent meta-analysis is the first to quantify its beneficial effects in a more general sense, it made the SuppVersity cut - especially in view of
    • the selected participants, i.e. competitive middle- or long-distance runners; with high fitness levels VO2max >60 ml/kg/min;
    • the exclusion of non-controlled trials or non peer-reviewed studies and/or studies that were shorter than 4 weeks,
    That only five studies met these inclusion criteria, tells you something about the extent of research (or non-extent) in this area.
    Table 1: Overview of the study results (Balsalobre-Fernández. 2016).
    With 4 of the 5 included studies using low to moderate training intensities (40–70% one repetition maximum), and all of them used low to moderate training volume (2–4 resistance lower-body exercises plus up to 200 jumps and 5–10 short sprints) 2–3 times per week for 8–12 weeks, it would for example be necessary to see if higher volumes or minimal volumes would have similarly "large, beneficial effect (standardized mean difference [95% confidence interval] = −1.42 [−2.23 to −0.60])" (Balsalobre-Fernández. 2016).
  • Barefoot running is the better endurance running (Berrones. 2016) - Being a competitive distance runner is, in part, attributable to a high V[Combining Dot Above]O2max. However, running economy (RE) is a more robust indicator of distance running performance among endurance athletes of similar VO2max levels.

    In a recent study scientists examined the influence of unshod (barefoot) vs. shod (wearing shoes) running on RE (expressed as ml/kg/min) during three 5-minute submaximal running trials representing 65, 75, and 85% of VO2max. Other physiologic and perceptual variables such as respiratory exchange ratio, lactate, heart rate, and ratings of perceived exertion were also chosen as dependent variables.
    Figure 1: Running barefoot, subjects did not get that close to their VO2max while running at a given speed; probably also due to the fact that their fat oxidation (RER) improved when barefood (Berrones. 2016).
    An analysis of the data the experiment generated showed that a 2-way (condition by intensity) repeated-measures analysis of variance. Submaximal oxygen consumption was significantly reduced at 85% of VO2max (p = 0.018), indicating an improvement in RE, but not during the 65% or 75% trials (p > 0.05, both).

    At least for the recreational or competitive distance runner, training or competing while barefoot may be thus be a useful strategy to improve endurance performance [note: the scientists didn't declare sponsoring a potential bias].
  • Warm-up? Yay, nay or maybe? New study shows whether stretching helps or harms depends on how you stretch (Sá. 2016) - The purpose of the study was to investigate the acute effects of 2 stretching interventions, proprioceptive neuromuscular facilitation (PNF) and passive static stretching (PSS), and a specific warm-up (SW) on the strength and architecture of the vastus laterallis and biceps femoris muscles in a subsequent performance on a strength training session (STS).

    Musculoskeletal ultrasound images were acquired from 9 men before and immediately after stretchings or a SW, and 10 minutes after a STS. The STS consisted of the following exercises: leg extension, leg curl, leg press, and hack machine squat.
    Figure 2:  Representative graph of the number of repetitions for each exercise and group. For p <= 0.05, (A) differences for the proprioceptive neuromuscular facilitation; (B) differences to the control; (C) difference between passive static stretching and specific warm-up (Sá. 2016).
    PNF resulted in lower performance for all situations. The PSS and SW improved performance for the leg press compared with the PNF and controls (CSs). For the hack machine squat, SWs resulted in higher performance than stretching conditions. The vastus lateralis muscle fascicle length (FL) increases after a STS for PNF. The biceps femoris muscle showed a higher pennation angle 10 minutes after the STS for PSS; the FL increases immediately after PSS and then decreases 10 minutes after the STS for PSS.

    "As per our results, the SWs should be performed before STSs, whereas PNF stretching should not be prescribed because this condition impairs subsequent performance," the authors conclude and state that "[t]hese results may assist health professionals in prescribing resistance training" (Sá. 2016).
Individual changes in strength in a 5-week study in NSCA Div II male basketball players (Joy. 2016)
Variable resistance - A thing to remember when striving for maximal gains: The results of another just published study should remind you that using variable resistance in form of resistance training bands as a component (not exclusively) of a periodized training program, can help you build power and strength. Whether it is more effective if you do that in the way it was done by Joy et al. (2016) and devote a whole training session per week to training with bands or whether you decide to incorporate certain exercises in every workout will yet have to be elucidated in future studies.
  • Can you HIIT it after a workout and still grow? Yes, you can! (Kikuchi. 2016) - The purpose of this study was to examine whether lower limb sprint interval training (SIT) after arm resistance training (RT) influences training response of arm muscle strength and hypertrophy. Twenty men participated in this study.

    The authors divided subjects into RT group (n = 6) and concurrent training group (CT, n = 6). The RT program was designed to induce muscular hypertrophy (3 sets × 10 repetitions [reps] at 80% 1 repetition maximum [1RM] of arm-curl exercise) and was performed in an 8-week training schedule performed 3 times per week on nonconsecutive days.
    Subjects assigned to the CT group performed identical protocols as strength training and modified SIT (4 sets of 30-s maximal effort, separated in 4 m 30-s rest intervals) on the same day.
    Table 2: Effect on VO2max, CSA, 1RM, and body weight of 8 wks of concurrent training (n = 6) and resistance training alone (n = 6 | Kikuchi. 2016).
    Pretest and posttest maximal oxygen consumption (VO2max), muscle cross-sectional area (CSA), and 1RM were measured.
    • Significant increase in VO2max from pretest to posttest was observed in the CT group (p = 0.010, effect size [ES] = 1.84) but not in the RT group (p = 0.559, ES = 0.35).
    • Significant increase in CSA from pretest to posttest was observed in the RT group (p = 0.030, ES = 1.49) but not in the CT group (p = 0.110, ES = 1.01).
    • Significant increase in 1RM from pretest to posttest was observed in the RT group (p = 0.021, ES = 1.57) but not in the CT group (p = 0.065, ES = 1.19).
    In conclusion, our data indicate that concurrent lower limb SIT interferes with arm muscle hypertrophy and strength.
  • How powerful would EPO be for you? Study says: it adds little to the benefits of training alone (Sieljacks. 2016) - The present study examines responses to 10 weeks of aerobic training and/or erythropoiesis-stimulating agent (ESA) treatment on maximal oxygen uptake (VO2max).

    Thirty-six healthy, untrained men were randomly assigned to sedentary-placebo (n = 9), sedentary-ESA (SE) (n = 9), training-placebo (TP) (n = 10), or training-ESA (TE) (n = 8). The participants were treated subcutaneously once weekly with ESA (darbepoietin-α, week 1–3; 40 μg and week 4–10; 20 μg) or a placebo for 10 weeks. The training consisted of supervised cycling 3 times per week for 1 hour at an average of 65% of maximal watt, with a progressive overload during the intervention period. VO2max, wattmax, and hematological values were measured throughout the study.
    Figure 2: Relation between delta changes in hematocrit and VO2max. The relation between delta changes in hematocrit (hct) and delta changes in VO2max (ml·min-1·kg-1). SP = Sedentary-placebo; SE = Sedentary-ESA; TP = Training-placebo; TE = Training-ESA (Sieljacks. 2016).
    In addition, the total training workload and estimated energy consumption were recorded after each training session. ESA treatment increased hemoglobin (∼11 and ∼14%, p < 0.001) and hematocrit (∼12 and ∼13%, p < 0.001) in the SE and TE groups, respectively. The relative (but not absolute) increases in VO2max were more pronounced (p < 0.01) in TE (27 ± 6%), compared with SE (15 ± 4%) but not TP (19 ± 4%), indicating that training is superior to ESA in stimulating VO2max in untrained men. The increased oxygen uptake in the TE group did not result in higher absolute training workloads than in the TP group.

    In untrained [don't forget this qualifier] men, training exhibits a greater stimulus for improvements in VO2max than ESA treatment, without pronounced additive effects, which is supported by similar average training workloads and energy consumption in TP and TE. Thus, in untrained men, training alone seems sufficient to induce improvement in VO2max.
  • Portable lactate measurement device - a gadgets that works (Borges. 2016) - A commercially available device claiming to be the world's first wearable lactate threshold predicting device (WLT), using near-infrared LED technology, has entered the market.

    Figure 3: A) The wearable lactate threshold predicting device (WLT | BSXinsight multi-sport edition) and (B) the compression calf sleeve that the WLT it is housed in, positioned over the gastrocnemius calf muscle. 1 = 3 near infrared LED's; 2 = charging connector pins (Borges. 2016).
    The aim of this study was to determine the levels of agreement between the WLT-derived lactate threshold workload and traditional methods of lactate threshold (LT) calculation and the interdevice and intradevice reliability of the WLT. Fourteen (7 male, 7 female; mean ± SD; age: 18–45 years, height: 169 ± 9 cm, mass: 67 ± 13 kg, VO2max: 53 ± 9 ml·kg−1·min−1) subjects ranging from recreationally active to highly trained athletes completed an incremental exercise test to exhaustion on a treadmill. Blood lactate samples were taken at the end of each 3-minute stage during the test to determine lactate threshold using 5 traditional methods from lactate analysis which were then compared to the WLT predicted value.

    In a subset of the population (n = 12), repeat trials were performed to determine both inter-reliability and intrareliability of the WLT device. Intraclass correlation coefficient (ICC) found high to very high agreement between the WLT and traditional methods (ICC > 0.80), with TEMs and mean differences ranging between 3.9–10.2% and 1.3–9.4%. Both interdevice and intradevice reliability resulted in highly reproducible and comparable results (CV < 1.2%, TEM <0.2 km·h−1, ICC > 0.97).

    Accordingly, the scientists conclude that their "study suggests that the WLT is a practical, reliable, and noninvasive tool for use in predicting LT in runners" (Borges. 2016).
  • 80% and 30% intensity resistance training produces identical hypertrophy (Jenkins. 2016) - IIRC, I wrote about this study before, but the fact that it demonstrates the equalty of the hypertrophic, strength, and neuromuscular adaptations to 2 and 4 weeks of resistance training at 80 vs. 30% 1 repetition maximum (1RM) in untrained men makes it worth reviewing, anyways.

    Fifteen untrained men (mean ± SD; age = 21.7 ± 2.4 years; weight = 84.7 ± 23.5 kg) were randomly assigned to either a high-load (n = 7) or low-load (n = 8) resistance training group and completed forearm flexion resistance training to failure 3 times per week for 4 weeks. Forearm flexor muscle thickness (MT) and echo intensity, maximal voluntary isometric (MVIC) and 1RM strength, and the electromyographic, mechanomyographic (MMG), and percent voluntary activation (%VA) responses at 10–100% of MVIC were determined at baseline, 2, and 4 weeks of training.
    Figure 4: Muscle thickness and maximal voluntary contraction over the course of the study (Jenkins. 2016).
    The MT increased from baseline (2.9 ± 0.1 cm) to week 2 (3.0 ± 0.1 cm) and to week 4 (3.1 ± 0.1 cm) for the 80 and 30% 1RM groups. MVIC increased from week 2 (121.5 ± 19.1 Nm) to week 4 (138.6 ± 22.1 Nm) and 1RM increased from baseline (16.7 ± 1.6 kg) to weeks 2 and 4 (19.2 ± 1.9 and 20.5 ± 1.8 kg) in the 80% 1RM group only. The MMG amplitude at 80 and 90% MVIC decreased from baseline to week 4, and %VA increased at 20 and 30% MVIC for both groups. Resistance training to failure at 80 vs. 30% 1RM elicited similar muscle hypertrophy, but only 80% 1RM increased muscle strength.

    The scientists are yet right to point that "[h]owever, these disparate strength adaptations were difficult to explain with neuromuscular adaptations because they were subtle and similar for the 80 and 30% 1RM groups" (Jenkins. 2016). In fact, there appears to be trend towards a decline in the adaptational strength response to light intensity training over time. If this occurs in noobs, it will probably be there right from the beginning in trained individuals for whom the results of the study at hand are at best "hardly relevant".
You cannot wrap your head around the results? You do not understand why study subjects count and the Jenkins study doesn't tell you anything about someone as trained as yourself? Maybe it's time to HIIT it, then (you know that you can do that after reading the Kikuchi study), because the last study in today's news potpourri demonstrates that interval running training improves cognitive flexibility (and, obviously) aerobic power of young healthy adults (Venckunas. 2016).

Figure 5: Cognitive performance at baseline and posttraining in experimental and control groups (only stat. sign. different parameters plotted | Venckunas. 2016)
The study was conducted in eight not exactly unfit young dinghy sailors (6 boys and 2 girls) completed the interval running program with 200 m and 2,000 m running performance, cycling maximal oxygen uptake, and cognitive function was measured before and after the intervention. The control group consisted of healthy age-matched subjects (8 boys and 2 girls) who continued their active lifestyle and were tested in the same way as the experimental group, but did not complete any regular training. In the experimental group, 200 m and 2,000 m running performance and cycling maximal oxygen uptake increased together with improved results on cognitive flexibility tasks | Comment!
  • Balsalobre-Fernández, C, Santos-Concejero, J, and Grivas, GV. Effects of strength training on running economy in highly trained runners: a systematic review with meta-analysis of controlled trials. J Strength Cond Res 30(8): 2361–2368, 2016
  • Berrones, AJ, Kurti, SP, Kilsdonk, KM, Cortez, DJ, Melo, FF, and Whitehurst, M. Barefoot running reduces the submaximal oxygen cost in female distance runners. J Strength Cond Res 30(8): 2348–2353, 2016
  • Borges, NR and Driller, MW. Wearable lactate threshold predicting device is valid and reliable in runners. J Strength Cond Res 30(8): 2212–2218, 2016
  • Jacobson, BH, Conchola, EC, Smith, DB, Akehi, K, and Glass, RG. Relationship between selected strength and power assessments to peak and average velocity of the drive block in offensive line play. J Strength Cond Res 30(8): 2202–2205, 2016
  • Jenkins, NDM, Housh, TJ, Buckner, SL, Bergstrom, HC, Cochrane, KC, Hill, EC, Smith, CM, Schmidt, RJ, Johnson, GO, and Cramer, JT. Neuromuscular adaptations after 2 and 4 weeks of 80% versus 30% 1 repetition maximum resistance training to failure. J Strength Cond Res 30(8): 2174–2185, 2016
  • Joy, JM, Lowery, RP, Oliveira de Souza, E, and Wilson, JM. Elastic bands as a component of periodized resistance training. J Strength Cond Res 30(8): 2100–2106, 2016
  • Kikuchi, N, Yoshida, S, Okuyama, M, and Nakazato, K. The effect of high-intensity interval cycling sprints subsequent to arm-curl exercise on upper-body muscle strength and hypertrophy. J Strength Cond Res 30(8): 2318–2323, 2016
  • Sá, MA, Matta, TT, Carneiro, SP, Araujo, CO, Novaes, JS, and Oliveira, LF. Acute effects of different methods of stretching and specific warm-ups on muscle architecture and strength performance. J Strength Cond Res 30(8): 2324–2329, 2016
  • Sieljacks, P, Thams, L, Nellemann, B, Larsen, MS, Vissing, K, and Christensen, B. Comparative effects of aerobic training and erythropoietin on oxygen uptake in untrained humans. J Strength Cond Res 30(8): 2307–2317, 2016
  • Venckunas, T, Snieckus, A, Trinkunas, E, Baranauskiene, N, Solianik, R, Juodsnukis, A, Streckis, V, and Kamandulis, S. Interval running training improves cognitive flexibility and aerobic power of young healthy adults. J Strength Cond Res 30(8): 2114–2121, 2016