Science
The research the BLOCKS assistant answers from: 1,118 studies and 81 guides, each graded for how strong the evidence is and who it was measured on, with a link to the original paper.
118 entries in Strength & power
A-Do light loads grow slow-twitch fibres more than heavy ones?Not shown: in 8 small biopsy trials type I growth was flat across loads; type II grew a little more with heavy loads, all CIs crossing zero. Mostly untrained.Varovic 2026BDo on-bike isometric pushes at crank angles raise sprint power?In 24 elite track sprinters, 6 weeks of 3-s max pushes at 3 angles instead of the heavy lift: W/kg +4.3% vs −0.5%; watts +2.9%, not above controls. Not randomised.Kordi 2020B+Will slow bodyweight strength work make a runner faster?In 34 soldier-runners, 4 wk of 84-s sets (7-s reps) raised knee torque and jump; 3000 m gains (−2.8% vs −0.8% in controls) were not significant. Short, underpowered; no economy data.Martins 2026C+Do slow reps switch on mitochondria?One bout of 30% 1RM at 6 s up/6 s down to failure raised mitochondrial protein synthesis 114% at 0-6 h; fast reps short of failure did not, but both did by 24-30 h. n=8, acute, not mitochondrial…Burd 2012BDoes light lifting to failure add capillaries and mitochondria?In 10 men, 6 wk of 30% 1RM squats to failure raised type I capillary contacts ~18% and respiration ~30%, not mitochondrial proteins. Normal tempo; no non-training control.Pignanelli 2020B+Do light loads to failure build slow fibres and mitochondria?In 21 men, 30% 1RM to failure grew type I fibres like 80% and alone raised mitochondrial dynamics proteins; volume-matched 30% short of failure did not. Tempo unstated; ~7/arm.Lim 2019A-Do slower reps build more muscle?In 14 trials, ~3.5-s reps grew muscle no better than ~1-s reps (difference 0.09 favouring faster, CrI −0.04 to 0.22). Usually one phase was slowed; reps over 4.5 s were not tested.Enes 2025A-Does a slow tempo grow more muscle?A meta-analysis of 8 trials to failure found similar growth for reps of 0.5-8 s; reps over 10 s looked worse (few studies). Muscle size only: no fibre-type, mitochondrial or endurance data.Schoenfeld 2015BDoes slow, no-relaxation squatting make you more powerful?In 16 young men, 8 weeks of 50% 1RM squats at 3 s down / 3 s up grew the quads 6-10% and squat 1RM 10%; jump height and leg power did not change significantly.Usui 2016BDoes slow, no-relaxation squatting change how you pedal?In 24 non-cyclists, 13 weeks of LST squats made pedal force and quad EMG more even (variation -18%, -21%); heavy squats did not. Performance effect unknown.Tanimoto 2009B+Does whole-body slow, no-relaxation lifting at ~55-60% 1RM work?In 36 untrained men, 13 weeks twice weekly: muscle thickness +6.8% and 1RM +33% vs +9.1% and +41% with ~80-90% 1RM. About three-quarters of the heavy gains; abstract only.Tanimoto 2008B+Does slow, no-relaxation lifting at ~50% 1RM build muscle?In 24 untrained men, 12 weeks of 3 s up / 3 s down to failure grew the quads like ~80% 1RM (+5.4% vs +4.3%); normal speed at that load did not. Small trial.Tanimoto & Ishii 2006C+Does no-relaxation training at 50% 1RM match heavy lifting?The IBMP lab's summary: it builds strength and size, but less than 80-85% 1RM, with growth shifted to type I fibre area. Abstract only, no numbers.Vinogradova 2013BDoes no-relaxation training at 50% of max build muscle?In 18 active men over 8 weeks: strength +21%, volume +9%, vs +35% and +17% at 80% MVC (difference not significant, 9 per group). Abstract only.Popov 2006A-Does training at long muscle lengths grow more muscle?A Bayesian meta-analysis of 12 small trials found only trivial extra regional growth (SMD 0.05-0.09), slightly more distally. Mostly untrained people, modest length contrasts.Varovic 2025B+Does a mid-thigh pull show strength in movement?In 47 correlational studies, IMTP force tracked 1RM squat (r 0.71-0.97) and related to jumps and sprints, explaining 12-94% of variance. A proxy, not a 1RM; no endurance data.Lum 2020B+Is the mid-thigh pull a trustworthy strength test?Across 16 studies peak force repeated well (median ICC 0.96, CV 4.9%). Mostly team-sport athletes; standardise the position. A change under ~5% is noise; only clearly larger ones count.Grgic 2022BPush or hold for isometrics?In 10 adults over 6 weeks, pushing at 70% MVC raised concentric and eccentric strength; holding a load did not, but grew the quadriceps more. Mostly small effects; a first signal only.Lum 2026B+Can isometric holds replace full-range lifting for quad size?In 23 trained lifters over 6 weeks, long-length isometric knee extension grew the front thigh about as much as full-range reps (difference -0.20 cm, uncertain).Varovic 2025B+Explosive or slow isometric reps?In untrained men over 12 weeks, 3-s holds at 75% raised max strength 23% and quad size 8.1%; 1-s fast-and-hard reps gave 17% and alone improved force in the first 100 ms.Balshaw 2016C+How much isometric work, and how hard?A narrative review (no pooled data) suggests 70-75% MVC, 3-30 s holds, >80-150 s a session for size, and 80-100% MVC, 1-5 s, 30-90 s a session for maximal strength.Lum & Barbosa 2019B+Does an isometric hold only strengthen that one angle?Knee holds at 65 degrees for 4 weeks gave +12% there, +5 to 11% at nearby angles and nothing 30 degrees deeper. Untrained men, one leg; train near the angle you need.Lanza 2019A-Long or short muscle length for isometric holds?In 26 small trials in non-athletes, long-length holds grew muscle faster (1.16 vs 0.47%/week, 3 studies) and spread strength to more angles; over 9 studies the gap shrank (0.88 vs 0.61).Oranchuk 2019BIsometric and plyometric training, added twice a week for 6 weeks, both improved 2.4-km time-trial time, maximal aerobic speed, jump height and isometric mid-thigh pull force more than a bodyweight circuit in endurance runners; the authors' claim that isometrics improved running economy more rests on a time effect, not a significant group differenceLum 2023BHeavy isometric calf training lowered the energy cost of running about 4% in recreational runners14 weeks of 90% MVC isometric plantarflexion (5 × 4 × 3 s, 3-4×/week) raised plantarflexor strength 10% and Achilles stiffness 31%, and the soleus then shortened at more efficient speeds; the fall in…Bohm 2021BHeavy isometric calf training made running about 4% cheaper14 weeks of 90% MVC isometric plantarflexion (5 × 4 × 3 s, 4×/week) raised plantarflexor strength ~7% and triceps surae tendon stiffness ~16% and cut the oxygen cost of running at 3.0 and 3.5 m/s ~4%…Albracht & Arampatzis 2013B+Strength training improves running economy durability and fatigued high-intensity performance in well-trained male runners10 weeks of twice-weekly heavy lifting plus jumps cut the economy drift over a 90-min run (4.7% to 2.1% from minute 15 to 90) and lengthened a run to exhaustion straight after it by 35%, while fresh…Zanini 2025C+Minimal-dose resistance exercise for people who do not liftOne session a week, one set per exercise, daily "snacks", practising a maximal lift or a few maximal eccentric contractions each raise strength over doing nothing; once-weekly and single-set training…Nuzzo 2024B+Four velocity-loss thresholds in the full squat at 55-70% 1RM (0, 10, 20 and 40%): 20% gave the largest 1RM and heavy-load velocity gains; 40% showed the largest muscle-size effect size but no significant group difference, and the smallest strength gainsSánchez-Valdepeñas 2026BEight weeks of progressive Copenhagen adduction training raised eccentric hip-adduction strength by 35.7% in young footballers, with little muscle sorenessIshøi 2016A-A single adductor exercise (the Copenhagen adduction) cut the prevalence of groin problems in male footballers from 21.3% to 13.5% over a season (OR 0.59)Harøy 2019B-Eight weeks of core training raised plank endurance, but running economy did not differ from the control groupThe reported improvement is a within-group change without a group × time interactionHung 2019A-Core training improves balance and jumping in pooled randomized trials; no endurance outcome was pooled, so it gives no support for better running or cycling performanceRodríguez-Perea 2023C+Strategies to improve running economyBarnes & Kilding 2014C+A Performance Analysis of HYROX: A Review of the Physiologic, Mechanical, and Technical DemandsDavids 2025B-High Intensity Functional Training in Hybrid Competitions: A Scoping Review of Performance Models and Physiological AdaptationsVillarroel López 2025BPrevalence, burden and risk markers of health problems in HYROX athletes: a 12-week prospective cohort studyChittenden 2026B+Longitudinal performance development in PRO and ELITE HYROX competitions across the first seven competitive seasonsRappelt 2026BRelative Running Intensity and Pacing During an Official HYROX PRO MEN Competition: The HYScience StudyGutiérrez-Hellín 2026B+Where am I struggling? Detailed benchmarks for every workout and category in Hyrox© competitionFernández-Navarrete 2026