Agonist and Stabilizer Muscle Activity during a Push Up on Unstable Surfaces

A recent trend among fitness professionals is to have clients perform resistance exercises on unstable equipment. Anecdotally, this is done with the intent that stabilizing and agonist muscles are more active while doing certain exercises on unstable surfaces. However, there are limited data as to whether or not this is the case and no studies have investigated muscle activity while doing the same exercise on surfaces that offer different levels of stability. Therefore, the purpose of this study is to measure electromyography (EMG) during push up exercise performed on unstable surfaces as well as on the ground. Surface EMG was measured at 6 muscles (Pectoralis Major, Anterior Deltoid, Tricep Brachii, Latissimus Dorsi, Rectus Abdominus, External Oblique) while participants performed push ups on 3 different surfaces: ground, stability ball, suspension trainer. A repeated measures analysis of variance (ANOVA) was used to compare average and root mean square (RMS) EMG across three repetitions between surface conditions for each muscle. A Sidak planned main effects multiple comparison was used to compare differences between conditions. For each muscle, average EMG and RMS EMG was influenced by surface the push ups were performed on (p\u3c.05). The suspension training system showing increased muscle activity in four of the measured muscles (Tricep Brachii, Latissimus Dorsi, Rectus Abdominus, and External Oblique); the ball showing increased EMG in the Pectoralis Major; and the ground showing increased EMG for the Anterior Deltoid. Doing push ups on unstable surfaces results in an increased muscle activity of stabilizing muscles. Furthermore, the type and level of stability of the surface influences muscle activity

SO₂, silicate clouds, but no CH₄ detected in a warm Neptune

WASP-107b is a warm (approximately 740 K) transiting planet with a Neptune-like mass of roughly 30.5 M ⊕ and Jupiter-like radius of about 0.94 R J (refs. 1,2), whose extended atmosphere is eroding 3. Previous observations showed evidence for water vapour and a thick, high-altitude condensate layer in the atmosphere of WASP-107b (refs. 4,5). Recently, photochemically produced sulfur dioxide (SO2) was detected in the atmosphere of a hot (about 1,200 K) Saturn-mass planet from transmission spectroscopy near 4.05 μm (refs. 6,7), but for temperatures below about 1,000 K, sulfur is predicted to preferably form sulfur allotropes instead of SO2 (refs. 8–10). Here we report the 9σ detection of two fundamental vibration bands of SO2, at 7.35 μm and 8.69 μm, in the transmission spectrum of WASP-107b using the Mid-Infrared Instrument (MIRI) of JWST. This discovery establishes WASP-107b as the second irradiated exoplanet with confirmed photochemistry, extending the temperature range of exoplanets exhibiting detected photochemistry from about 1,200 K down to about 740 K. Furthermore, our spectral analysis reveals the presence of silicate clouds, which are strongly favoured (around 7σ) over simpler cloud set-ups. Furthermore, water is detected (around 12σ) but methane is not. These findings provide evidence of disequilibrium chemistry and indicate a dynamically active atmosphere with a super-solar metallicity.</p

SO2, silicate clouds, but no CH4 detected in a warm Neptune

International audienceWASP-107b is a warm ($\sim$740 K) transiting planet with a Neptune-like mass of $\sim$30.5 $M_{\oplus}$ and Jupiter-like radius of $\sim$0.94 $R_{\rm J}$, whose extended atmosphere is eroding. Previous observations showed evidence for water vapour and a thick high-altitude condensate layer in WASP-107b's atmosphere. Recently, photochemically produced sulphur dioxide (SO$_2$) was detected in the atmosphere of a hot ($\sim$1,200 K) Saturn-mass planet from transmission spectroscopy near 4.05 $\mu$m, but for temperatures below $\sim$1,000 K sulphur is predicted to preferably form sulphur allotropes instead of SO$_2$. Here we report the 9$\sigma$-detection of two fundamental vibration bands of SO$_2$, at 7.35 $\mu$m and 8.69 $\mu$m, in the transmission spectrum of WASP-107b using the Mid-Infrared Instrument (MIRI) of the JWST. This discovery establishes WASP-107b as the second irradiated exoplanet with confirmed photochemistry, extending the temperature range of exoplanets exhibiting detected photochemistry from $\sim$1,200 K down to $\sim$740 K. Additionally, our spectral analysis reveals the presence of silicate clouds, which are strongly favoured ($\sim$7$\sigma$) over simpler cloud setups. Furthermore, water is detected ($\sim$12$\sigma$), but methane is not. These findings provide evidence of disequilibrium chemistry and indicate a dynamically active atmosphere with a super-solar metallicity