The experience of laser light feedback in back-squat resistance training.

Introduction: The purpose of this paper is to contribute to the existing literature on performance in resistance training (RT) by addressing how a phenomenological perspective on experiences with inter kinaesthetic affectivity can illuminate experience of practicing RT with non-verbal, visual feedback provided through laser lights attached to the barbell. Method: The material is created from qualitative interviews and using inter-kinaesthetic affectivity as analytical lenses. Results: The findings show how participants interpret the feedback in the moment and explain how they adjust their movement in dialogue with the feedback and enable the "uptake" of feedback in their embodied experience. The findings show how the participants developed an awareness of how they can equalize the balance on their feet. Discussion: We discuss what this means for the understanding of the training process in terms of how practitioners can use the uptake of non-verbal, visual feedback to immediately adjust the quality of their performance by responding kinaesthetically and bodily. The discussion contributes to the question of what kind of role a practitioner's own kinaesthetic and bodily experiences have in the development and organization of RT. Perspectives that include the lived and intersubjective body as a knowledge position are promising for illuminating the whole bodied engagement that is necessary to understand how to perform RT.

The effects of technological and traditional feedback on back squat performance in untrained women.

BACKGROUND: Recently, a novel method for improving movement quality called open-ended augmented feedback has been introduced. However, the effects of using such feedback in a training intervention have not yet been examined. The aim of this study was to assess the changes in performance and movement quality following a five-week resistance-training program with either (1) technological feedback or (2) traditional, verbal feedback from an experienced trainer. METHODS: Nineteen untrained females (age: 21.84 ± 2.24 years, height: 169.95 ± 5.92 cm, body mass: 65.05 ± 7.93 kg) randomly allocated to one of the two conditions completed five weeks of training with two weekly sessions. Pre- and post-intervention, participants were tested for physical performance (i.e., back squat and isometric mid-thigh pull strength) and movement quality parameters (weight distribution, center of gravity variation, and subjective rating of the back squat technique). RESULTS: Both groups similarly increased the training resistance throughout the intervention (p < 0.01), as well as strength in the back squat (technological feedback group: effect size (ES) = 1.31, p = 0.002; traditional feedback group: ES = 1.48, p = 0.002). Only the traditional feedback group increased isometric mid-thigh pull strength (ES = 1.11, p = 0.008) and subjectively rated lifting technique at the same load (p = 0.046). No changes in force distribution (p = 0.062-0.993) or center of gravity variation (p = 0.160-0.969) occurred in either group when lifting the same absolute loads at post-test. However, both groups displayed a greater variation in center of gravity when lifting the same relative load at post-test (technological feedback group: p < 0.001; traditional feedback group: p = 0.006). No differences were found between the groups for any of the observed changes (p = 0.205-0.401). CONCLUSIONS: Five weeks of back-squat training with verbal feedback increased isometric mid-thigh pull strength and subjectively rated lifting technique from pre- to post-test, whereas technological feedback did not. Both methods improved back squat strength and training resistance. For resistance-training beginners, the choice between feedback methods should be based on the desired outcomes and the availability of expertise and equipment.

Algal toxins as guidance to identify phosphoproteins with key roles in apoptotic cell death.

The protein phosphatase inhibiting toxins microcystin and nodularin act rapidly to induce apoptotic cell death. Their inhibitory effect on protein phosphatases 1 and 2A can be utilized as tools to understand the phosphorylation-dependent regulatory mechanism underlying the early stage of apoptosis. The incubation of freshly isolated hepatocytes with these toxins results in a rapid hyperphosphorylation of cellular proteins before any morphological signs of apoptosis appears [Fladmark, K. E., Brustugun, O. T., Hovland, R., Boe, R., Gjertsen, B. T., Zhivotovsky, B. and Doskeland, S. O. (1999) Cell Death Differ. 6, 1099-108]. Proteins subjected to phosphorylation in this early phase of apoptosis may play key roles in this cellular process and become valuable targets for drug development. The ultra-rapid apoptosis-induction by microcystin and nodularin provides a unique amount of synchronized apoptotic cells with "large" amounts of mainly serine/threonine phosphorylated proteins. This ultra-rapid toxin-induced up-concentration of phosphorylated proteins reduces the material needed as well as simplifies our effort in order to obtain enough phosphoproteins for mass spectrometric identification and characterization. We will here give an overview of our strategy for identification of low-abundance phosphoproteins involved in algal toxin-induced apoptosis and most likely also in a general apoptotic pathway.

Microheterogeneity of recombinant human phenylalanine hydroxylase as a result of nonenzymatic deamidations of labile amide containing amino acids. Effects on catalytic and stability properties.

The microheterogeneity of recombinant human phenylalanine hydroxylase (hPAH) was investigated by isoelectric focusing and 2D electrophoresis. When expressed in Escherichia coli four main components (denoted hPAH I-IV) of approximately 50 kDa were observed on long-term induction at 28-37 degrees C with isopropyl thio-beta-D-galactoside (IPTG), differing in pI by about 0.1 pH unit. A similar type of microheterogeneity was observed when the enzyme was expressed (1 h at 37 degrees C) in an in vitro transcription-translation system, including both its nonphosphorylated and phosphorylated forms which were separated on the basis of a difference in mobility on SDS/PAGE. Experimental evidence is presented that the microheterogeneity is the result of nonenzymatic deamidations of labile amide containing amino acids. When expressed in E. coli at 28 degrees C, the percentage of the acidic forms of the enzyme subunit increased as a function of the induction time with IPTG, representing about 50% on 8 h induction. When the enzyme obtained after 2 h induction (containing mainly hPAH I) was incubated in vitro, its conversion to the acidic components (hPAH II-IV) revealed a pH and temperature dependence characteristic of a nonenzymatic deamidation of asparagine residues in proteins, with the release of ammonia. Comparing the microheterogeneity of the wild-type and a truncated form of the enzyme expressed in E. coli, it is concluded that the labile amide groups are located in the catalytic domain as defined by crystal structure analysis [Erlandsen, H., Fusetti, F., Martínez, A., Hough, E., Flatmark, T. & Stevens, R. C. (1997) Nat. Struct. Biol. 4, 995-1000]. It is further demonstrated that the progressive deamidations which occur in E. coli results in a threefold increase in the catalytic efficiency (Vmax/[S]0.5) of the enzyme and an increased susceptibility to limited tryptic proteolysis, characteristic of a partly activated enzyme. The results also suggest that deamidation may play a role in the long term regulation of the catalytic activity and the cellular turnover of this enzyme.