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Background: Two commonly used strength training exercises are the chin-up- and the lat-pulldown exercise. Both exercises are performed by using similar movement patterns and by using the same primary muscles. Previous research has shown that each exercise can exhibit unique training stimulus and should not be considered interchangeably. However, there is limited research regarding comparison of muscle activation between the exercises. Knowing the amount of muscle activation when performing the exercises, can help strength training participants to choose exercise and relative workload according to the specific muscles they want to target. Purpose: This study sought to compare muscle activation (measured as average) in m. latissimus dorsi (LD), m. biceps brachii (BB), middle m. trapezius (TR) and m. rectus abdominis (RA) between performing the chin-up at 100% of participants’ individual bodyweight (BW) with lat-pulldown at 50%-, 65%- and 75% BW. Methods: Twenty strength trained male participants (25.0 ± 3.3 yr; 181.0 ± 5.8 cm; 82.0 ± 7.8 kg) were examined during the study. Surface electromyography (SEMG) was collected from LD, BB, TR & RA during the exercises. Average muscle activation was expressed as percentage of maximum voluntary isometric contraction (%MVIC). Exercise execution was as identical as possible for both exercises and was performed using pronated handgrip and a grip width equal to 1.5 times the participants individual biacromial distance. Results: Statistically significant (p<0.05) increases in average muscle activation were found in LD, BB and RA during chin-up 100% BW compared to lat-pulldown at 50%-, 65% and 75% BW. However, for TR no significant difference (p=0.145) was found between chin-up 100% BW and lat-pulldown when performed at 75% BW. Conclusion: These results indicate that performing the lat-pulldown using workload somewhere between 75-100% BW can exhibit the same muscle activation as performing the chin-up at 100% BW. Keywords: Strength training, Surface electromyography, Muscle activation, Chin-up exercise, Latpulldown exercise, Different workloads, Randomisation, Cross-over, Observational

Total lungkapacitet (TLC) är den totala volymen gas i lungorna efter en maximal inspiration. Den kan beräknas med kroppspletysmograf utifrån tryckförändringar och Boyles lag respektive utifrån gasspädning med metan alternativt helium som spädningsgas. Vanligen används kroppspletysmografi och för att kunna använda metangasspädning som substitut är överensstämmelsen mellan metoderna av intresse. Studiens syfte var att jämföra TLC från single-breath metangasspädning med TLC från kroppspletysmografi. Data gällande patienter som genomgått båda undersökningarna vid samma tillfälle enligt standardförfarande samlades in. Studien var en retrospektiv tvärsnittsstudie och populationen á 48 patienter innehöll lika många män som kvinnor, åldrar från 10 till 87 år samt med och utan angivna respiratoriska sjukdomar. TLC från kroppspletysmografin sträckte sig från 2,6 till 8,4 liter och TLC från metangasspädningen sträckte sig från 2,5 till 7,7 liter. TLC från gasspädningen var i genomsnitt 0,59 liter mindre än TLC från kroppspletysmografin. Metangasspädningen underskattade TLC med 11,3%. Skillnaden mellan kroppspletysmografins TLC och metangasspädningens TLC var signifikant vilket fastställdes med t-test för parvisa observationer. På grund av studiepopulationens natur finns behov av ytterligare studier med större populationer. TLC från metangasspädningen uppgick till 88,7% av TLC från kroppspletysmografin och gasspädning kan inte utan ökad risk för underskattning av TLC användas som substitut för kroppspletysmografi. / Total lung capacity (TLC) is the gas volume in the lungs after maximal inspiration. It can be calculated using whole-body plethysmography, pressure changes and Boyle’s law, or using gas dilution with methane or helium as inert gas. Agreement between the methods is of interest to make substitution of the more commonly used whole-body plethysmography with methane dilution possible. This retrospective cross-sectional study aimed to compare TLC from single-breath methane dilution with TLC from whole-body plethysmography. Data concerning patients who underwent these two standard procedure examinations in one visit was collected. The population of 48 had an even gender distribution, included ages 10 to 87 and patients with or without known respiratory diseases. TLC from whole-body plethysmography ranged between 2,6 and 8,4 liters. TLC from methane dilution ranged between 2,5 and 7,7 liters. TLC from gas dilution averaged 0,59 liters less than TLC from whole-body plethysmography and underestimated TLC by 11,3%. Paired samples t-test determined the difference between methods to be significant. Due to the nature of this population, further studies of larger populations are needed. Methane dilution TLC amounted to 88,7% of TLC from whole-body plethysmography which therefore cannot be substituted with methane dilution without increased risk of underestimating TLC.

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