mattyv

The Ubuntu One Music store, slated for release with Ubuntu 10.04 just went into public beta. Since I have Lucid running in Virtualbox OSE it seemed like a good thing to test. As the public beta blog entry lists a number of things to test, I decided to look at those specifically.

MP3 codec detection

This copy of Lucid was quite raw, no MP3 codecs.

Easily handled, installation worked seamlessly

Then I hit a hurdle. The main pane in Rhythmbox was blank (white) for quite some time, eventually loading an Ubuntu One Music Store error page, as shown to the right.

Generic error message from Ubuntu One Music Store, within Rhytmbox

This was partially to be expected, as I hadn’t at that point configured or used Ubuntu One on that virtual machine. I tried setting my Ubuntu One preferences via the System menu, however it crashed the first time. The second try opened Firefox and allowed me to login and add the computer. It would have been nice if that could be handled directly through Rhythmbox, given it was quite confusing and only my prior knowledge of the preferences menu allowed it to be overcome quickly. The plugin page within Rhythmbox also provided no options and no clues.

Take two, having paired the virtual computer with Ubuntu One, worked fine and presented me with a home page of music.

We get there in the end

Leaving the store idle for a while seemed to make it non-responsive to commands, however after reloading Rhythmbox I was finally able to take a look around.

Search

Using the search function was quick, and the categories of search should be familiar to those using Rhythmbox eg. Artist, Album etc. Then I headed into Browse mode, again finding it easy and hiccup free. Eighteen genre based categories are available for browsing, which should be quite sufficient.

One track I came across seemed to be a video, so Rhythmbox warned me it was not in MP3 format. I tried to preview it anyway (this is testing, afterall) and naturally it failed. This left me with a blank white screen again. Right-clicking allows you to go back and everything is fine again. However, this might not be clear to a new user. Perhaps some browser-like buttons for the available controls (forward, back, stop, reload) should be introduced to the interface when browsing the Ubuntu One Music Store.

I moved onto browsing newly added items and picked an MP3 release, which had three available tracks. Previewing these was simple and no errors occurred. The previews lasted for 30 seconds, as described in the store help section. One thing that could do with some work on this screen is the indication for the track format. Under the cover art is a red box displaying the format and I presume the bitrate. When hovering over it we get the well-known web browser question mark cursor, but no tooltip. A good addition would be to make hovering display some more information, as one might expect with the cursor.

The tracks had a ‘Download’ option, which I clicked. For some reason this just resulted in an error page saying that downloading was unavailable. This kept happening, and the same page appeared when trying to go to my ‘Basket‘. It was also not clear if clicking on download would add the track to my basket, or start a single download/purchase immediately.

That’s all the testing I could do for now. Nothing would be added to the basket, not that I could pay for them anyway. This was just some beta testing for Ubuntu One :-)
It all looks promising, and certainly the idea of a public beta is to iron out the bugs like those I found. Perhaps my region (Australia) was the cause, but that was not clear at all. As a responsible member of the Ubuntu community, I will be searching for existing bug reports and providing feedback or new bugs where necessary. This was certainly not a rant post. Betas are made for testing, something we could all do with remembering given the past week’s bug spam over button placement.

Wonder if Technorati supports Open-ID, initial searches indicate not. Getting too many unlinked profiles :-/ In other news, jumped onto Identi.ca last night. Looks like a great alternative to Twitter. They even offer free cloud hosting, something I might take the up on.

The Background

Okay, if you’re reading this you can probably see some irony in the title of the article already. Of course, I intend this short review to point the flaws in many other internet tutorials about Plyo’s, so there’s a point to the title. The issue is simple, too many sites show you fancy jumping, bounding and hopping exercises, but they don’t tell you how to actually make them Plyomeytrics instead of plain old jumps, bounds and hops.

Take for example this video from Expert Village, purporting to show us some Plyo’s. I see some really fast step-ups, good speed training. Then we are shown a Medicine Ball Squat Toss (MBST), performed repeatedly at low intensity – so we’re getting a bit of strength and endurance training. No Plyometrics. “But”, you say. Hold it there, I know what you’re thinking. The MBST can be performed in a way that makes it Plyometric. The video does not demonstrate this.

The Science

To understand the flaw in the video, and in many other descriptions on the internet, we need to know what makes Plyometrics, Plyometrics.

Stretch-Shortening Cycle (SSC)

An SSC is the performance of a rapid concentric (shortening) contraction following an eccentric contraction (muscle lengthening while producing force) ¹. We see in the video of the squat, the trainer squats down, performing the eccentric stretch phase, then stands up, demonstrating the concentric phase. As demonstrated many times, correctly performed SSCs produce more power in a shorter amount of time than regular concentric contraction ¹.

Many researchers see the SSC as being beneficial because it promotes a build-up of elastic energy in the musculotendinous unit, then a rapid release of this energy that results in greater power output ². A further effect of a correct SSC is reported to be the inducement of stretch reflex activity during the concentric phase, again enhancing power output and explosiveness ³.

Amortisation Phase

This is where the video above falls down (no pun intended). For the elastic energy to be utilised (rather than dissipate) and the reflex activity to be induced, the SSC must be performed very rapidly. In particular, the switch between the eccentric and concentric phases must be absolutely minimal ⁴. The time between the two phases is called the Amortisation phase. This leaves Plyometric exercises with three main aspects:

1. Eccentric stretch phase
2. Amortisation phase
3. Concentric contraction

The Internet

What the articles and web pages I see on the internet lack is an appropriate Amortisation (Amortization if you’re American) phase. Our guide in the video was not nearly dynamic enough. By the time she started the upward part of the squat some of the elastic energy in her muscles and tendons would have dissipated. It was a regular squat.

Now that you know the difference between a Plyometric exercise and a normal strength exercise, see if you can pick the ones below. I hope reading this made sense and wasn’t toooo full of jargon. Please post a comment if something didn’t make sense.

Simple Plyometrics Workout – Youtube
How to Practice Jumping: Plyometrics Drill 2
Sport Fitness Advisor
Ghetto Jump Training – Embedded Youtube

1. Miyaguchi, K., & Demura, S. (2008). Relationships between stretch-shortening cycle performance and maximum muscle strength. Journal of Strength and Conditioning Research, 22, 19-24.

2. Winchester, J., Nelson, A., Landin, D., Young, M., & Schexneyder, I. (2008). Static stretching impairs sprint performance in collegiate track and field athletes. Journal of Strength and Conditioning Research, 22, 13-18.

3. Bosco, C., & Komi, P. (1982) as Cited in Winchester et al. (2008).

4. Dodd, D., & Alvar, B. (2007). Analysis of acute explosive training modalities to improve lower-body power in baseball players. Journal of Strength and Conditioning Research, 21, 1177-1182.

How to do Plyometrics Properly by Matt Vickers is licensed under a Creative Commons Attribution-Share Alike 3.0 Unported License.

Just a quick vent of frustration at myself.

Why am I only now starting to get work done regularly. Hate the stress. Have been here before, yet continue to put myself through it. The below list is not comprehensive and doesn’t list things I’ve already done, except for submissions from the last week or so. No matter how much I work now it’s difficult to see myself catching up again, especially with the Research Proposal, Snook Lab and Ethics all due really soon :-(

Current list of assignments and due dates…

Clinical Business:

• Work Site Assessment
• Business Plan – Not started. Due 12 May

Scientific Writing:

• Research Proposal – 30%. Final Draft Due 10 April

Ergonomics of Exercise:

• NIOSH Lifting Lab
• Snook Rolling Resistance Lab – Not started. Due 16 April
• Major Assignment – Not started. Due 21 May

Research Project:

• Ethics Submission – 50%. Submit by 16 April or it’s several months before it can go through, putting me behind for the rest of the year!

On a better note, might start blogging about my research project once a week. Something to keep me on track.

Sorry, updated the router firmware and made a mistake when transferring the settings – port 8080 was no longer being forwarded to the right computer.

Whoops!